Talk:Gregorian calendar/Archive 4

centuries have only one date for beginning and ending.

all centuries begin on January 1st on a year that ends with '01 and ends on December 31st with a year that ends with '00. Any other way is totally 100% wrong. Thus the 20th century began with January 1, 1901, and ended on December 31, 2000. That is why it was the 20th century. because it end with 20(00). This is the 21st century, because it started on January 1, 2001 and not on January 1, 2000, because that was the beginning of the last year of the last century. This is this century and it did start on January 1, 2001 and not before. And this century will end on December 31, 2100, because it ends the year with 21(00), not with December 31, 2099. This is the 21st century and that means it ends with the year 2100. It has nothing to do with leap years of anything else. The celebration that celebrated around the world at the beginning of this century was actually a whole year way to early. The majority of people and governments just plainly goofed up. Just like this decade starts on January 1, 2011 and it ends on December 31, 2020, not 2019 like too man people are already thinking about. I wish people would get this right.Bobbyr55 (talk) 01:46, 31 December 2014 (UTC)

Last country to adopt the Gregorian calendar?

It says here that the last country to adopt the Gregorian calendar was the Soviet Union in 1929. I found articles (referred below) that mention that the Soviet Union changed to the Gregorian calendar on February 14, 1918. In fact, I found articles stating that the USSR actually abandoned the Gregorian calendar in 1929 in favour of the "Eternal Calendar" consisting of 12 months, each made up of 30 days split into six 5-day weeks. Later in 1932 they switched to 6-day weeks, only coming back to the Gregorian proper in 1940. Can someone please check these facts and edit the page? I've put some of the links below. The first one is pretty comprehensive, but the others will help you double check.

http://www.sras.org/russian_holidays

https://www.worldslastchance.com/ecourses/lessons/changing-weeks-hiding-sabbath-ecourse/18/20th-century-soviet-calendar-reform.html

http://history1900s.about.com/od/1920s/a/sovietcalendar.htm

So does that make it the last country to adopt the Gregorian calendar (i.e. in 1940) or does that title pass to someone else? — Preceding unsigned comment added by 14.97.86.240 (talk) 18:33, 13 February 2015 (UTC)

There is certainly some confusion that needs to be sorted out. Adoption of the Gregorian calendar#Adoption in East Asia says that Russia adopted it in February 1918.

The graphical Timeline says that Russia adopted it in 1918; it also says that the Soviet Union did so in 1922. That seems wrong for starters. Russia had already converted almost 5 years before the USSR ever came into formal existence in 1922, so it's not like the USSR started out under the Julian calendar and only later switched to Gregorian. No, the pre-existing Russian change-over simply extended to the new political entity that came into existence on 30 December 1922, and that cannot be characterised as an "adoption".

Then there was the Soviet calendar, which was in use between 1929 and 1940. That means that 1929 is the year that the Soviets abandoned the Gregorian, not adopted it. (The relevance of 1930 escapes me entirely.) Whether the re-adoption counts for the purposes of saying which was the last country to make the switch, I'm not sure, but if it does count, the relevant date would be 1940, not 1929. For comparison, when the French abandoned the French Republican Calendar in 1805 after 12 years of use, and re-adopted the Gregorian, we don't quote 1805 as the date of Gregorian adoption in France. We always refer to its original adoption there in 1582. So why make an exception for the Soviet Union? The fact that the country's name and organisation changed matters not.

I prefer to say that Russia adopted the Gregorian in 1918; the Soviet interruption 1929-40 deserves a mention later in the article and a link to Soviet calendar, but let us please get the dates right. -- Jack of Oz ^{[pleasantries]} 21:43, 13 February 2015 (UTC)

I've been bold and made the above changes. But still feel free to discuss. -- Jack of Oz ^{[pleasantries]} 23:10, 13 February 2015 (UTC)

The expert on this is Joe Kress. Feel free to ping him. See Soviet calendar where he makes it clear by references to the date on the pages of e.g. Izvestia that the U.S.S.R. never stopped using the Gregorian calendar.

Per WP:TPO & WP:RBI, close comments by IP sockpuppet of banned User:Vote (X) for Change
The following discussion has been closed. Please do not modify it.
The five and six - day weeks resulting in thirty - day months were grafted on to the Gregorian calendar - 360 days of work weeks and five or six public holidays outside making up the 365/366 day Gregorian year. Dates such as August 31 prove this. However, the White Russian armies in the 1920's (Orthodox) were not keen on the Bolshevik reform - and of course the Orthodox church still uses the Julian calendar. Authorities in far - flung provinces were slow to make the change, so it's perfectly true that the U.S.S.R. was not wholly Gregorian till 1929. 156.61.250.250 (talk) 16:41, 14 February 2015 (UTC)

You're noting the difference between formal promulgation and practical implementation. I am quite, quite, quite sure that many people and communities in Italy, Poland, Spain and Portugal did not immediately switch to the Gregorian calendar on 15 October 1582, either. There would have been resistance and delays in the British switchover in 1752, particularly in their overseas colonies. Of course there will always be problems in implementing a change like this. That would be true even today, let alone in the days before instant mass communication. However, the main thing we need to focus on here is that Russia formally switched to the Gregorian in February 1918. Details of the less-than-uniform implementation of that policy can appear if they're available, but in a lower profile location in the article. -- Jack of Oz ^{[pleasantries]} 19:15, 14 February 2015 (UTC)

Considering that an encyclopedia article must be concise to be useful to the intended audience, I think it's OK to just mention the formal start of a change that was successful, and reduce emphasis (or even ignore) changes that were formally promulgated but weren't accepted by the populace and were later repealed.

An example of a somewhat recent change that has been slow to be accepted by the populace (and some governments) is the elimination of Greenwich Mean Time. If you ask the scientific community, they'll tell you it was renamed universal time in the 1930s. If you ask for an exact definition of GMT, they'll tell you there isn't one. Jc3s5h (talk) 13:45, 15 February 2015 (UTC)

Per WP:TPO & WP:RBI, close comments by IP sockpuppet of banned User:Vote (X) for Change
The following discussion has been closed. Please do not modify it.
I think it's useful to tell readers about the Eternal calendar and the French Revolutionary calendar. We mention the Decree of Canopus but that change never got off the ground at all. Regarding Jack of Oz's edits, he's done something with curly brackets but what's inside them doesn't seem to appear at all (at least not in my browser). Can you elucidate what's happening here? Re Greenwich Mean Time, if you look inside the Astronomical Almanack (I haven't consulted it for some years mind) there's a note that astronomers do not use the term "Greenwich Mean Time" because it's ambiguous. But astronomers are not lawyers. Lawyers go back in time (the doctrine of legal precedent) and will happily tell you that Greenwich Mean Time is the same now as it was in 1971. 156.61.250.250 (talk) 14:33, 15 February 2015 (UTC)

Turkey and the Gregorian calendar

In 1917 the Gregorian calendar was adopted by Turkey (Ottoman Empire) but not the Christian era. The calendar agreed with the Gregorian calendar except on the number of the year. On Dec. 6, 1925 a decision was made by the Republic of Turkey to adopt the Christian era as well. — Preceding unsigned comment added by Ybgursey (talk • contribs) 17:31, 23 February 2015 (UTC)

Per WP:TPO & WP:RBI, close comments by IP sockpuppet of banned User:Vote (X) for Change
The following discussion has been closed. Please do not modify it.
See Adoption of the Gregorian calendar#Timeline. 156.61.250.250 (talk) 09:55, 24 February 2015 (UTC)

Synthesis

I have reported this edit at WP:No original research/Noticeboard#Calendar synthesis?. Jc3s5h (talk) 15:49, 1 March 2015 (UTC)

7 months with 31 days, 4 with 30 and February's 28 (7x4) is an example of the GOD=7_4 algorithm/code

I added... The 7 months with 31 days, 4 with 30 and February's 28 (7x4) is an example of the GOD=7_4 algorithm/code. in the infobox. 120.151.205.179 (talk) 10:13, 18 August 2015 (UTC)

It's under Juche calendar. If you have any other issues with the infobox go take it up on the box's talk page. Arcorann (talk) 06:45, 21 August 2015 (UTC)

References

Julian calendar

Julian calendar was a kind of ancient Occidental solar calender is that right? SA 13 Bro (talk) 22:46, 14 September 2015 (UTC)

Sort of. It was ordered by Julius Caesar, so it is western and ancient. And it is solar. But it was still in use in Greece as an official government calendar until 1923, and it is still used by some branches of the Orthodox Church. So it is also modern. Jc3s5h (talk) 23:07, 14 September 2015 (UTC)

Jc3s5h That was the GREAT men! The ancient kind of solar calender is still using at the modern time... SA 13 Bro (talk) 23:22, 14 September 2015 (UTC)

Semi-protected edit request on 31 December 2015

the text says that Eatern Orthodox churches are using the old calendar but Romania and Bulgaria are orthodox but use the gregorian calendar 86.171.147.61 (talk) 18:04, 31 December 2015 (UTC)

Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format. Datbubblegumdoe^{[talk – contribs]} 02:49, 7 January 2016 (UTC)

England and Jan 1

The article is unclear or misleading about England's shift to "New Style Julian". It states that the change to January 1st was made (officially) in 1752, but that January 1st was regarded informally as New Year's Day, and gives an example from Samuel Pepys. So far, so good. It is left open just how far people thought of the year as starting in January, but the implication is that the January start was just an informal concept.

However, year-start on January 1st was in fact in formal (if not "official") written and printed usage in England before 1752. For example, in the London Newspaper The General Advertiser, issue number 4114 was dated Thursday December 31, 1747, and issue number 4115 was dated Friday January 1, 1748.

How general, and when, was public adoption of "New Style Julian?". Were the newspapers really living in different years from officialdom for nearly three months of every year? Could a knowledgeable contributor please clarify the article on this? Wyresider (talk) 23:43, 19 January 2016 (UTC)

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Reference cleanup and restructuring?

Please review this recent edit. The purpose is to have more consistent formatting, and to add links between footnotes and references. The mechanism was to add templates where they previously weren't used (though attempting not to change the visual presentation, where the presentation was already consistent). Jc3s5h correctly asserts that changing to templates unilaterally is contrary to WP:CITEVAR. Is there a consensus for or against this change?

(Note that there are also corrections and expansions to some of the citations mixed into this change. That's a separate issue.)

Nitpicking polish (talk) 18:35, 24 February 2016 (UTC)

Back when these citations were first cleaned up and put in the present format, I would have strongly opposed using citation templates. They had some horrible problems, like not being able to put too many citations on the page or else some of them wouldn't be rendered. The citation templates are better than they were, although I think there is a bit too much error checking. For example, putting February 29 for years that were leap years in the Julian calendar but not the Gregorian (like 1700) creates error messages. I'll go along with whatever consensus other editors come to. Jc3s5h (talk) 20:54, 24 February 2016 (UTC)

Inter Gravissimas (W. Spenser & R. T. Crowley, Trans.) paywalled. Is there an open source of this translation?

This is paywalled:

• Gregory XIII. (2002 [1582]). Inter Gravissimas(subscription required) (W. Spenser & R. T. Crowley, Trans.). International Organization for Standardization.

Is there another source for this translation of Inter Gravissimas?

--Geremia (talk) 20:41, 21 March 2016 (UTC)

Astronomers are subject to WP:RS and WP:V the same as anybody else

thread started by banned user. Fut.Perf. ☼ 18:29, 5 April 2016 (UTC)
The following discussion has been closed. Please do not modify it.
Jc3s5h has added a claim which, apart from making the nonsense statement that the vernal equinox is a certain number of days apart cites a source which gives the alleged separation to six places of decimals. This is unverifiable. It is said to relate to "near 2000" but a check cannot be made because how near is not specified. In some contexts 1900 might be "near 2000", in others 1995 might be rather far away. 77.98.244.158 (talk) 22:57, 28 March 2016 (UTC) Are you claiming that Meeus and Savoie (1992), p. 42 is not a reliable source? Dbfirs 19:46, 4 April 2016 (UTC) It's a question of verification. You've conspicuously failed to verify those six - figure decimal values. 77.98.244.158 (talk) 20:26, 4 April 2016 (UTC) I don't need to personally verify them, just to cite them from a WP:reliable source. "Jean Meeus explores the frequency of blue moons, planetary groupings, and a great deal more, as only this master of astronomical calculations could." Dbfirs 20:42, 4 April 2016 (UTC) What a joke. What have blue moons and planetary alignments have to do with the theory behind the calendar? 77.98.244.158 (talk) 20:53, 4 April 2016 (UTC) Read the second half of the cite. Dbfirs 07:09, 5 April 2016 (UTC) The cite contains 23 words. So the second half of it is "a great deal more, as only this master of astronomical calculations could". Are you Jan Meeus' PR agent? How does that verify a time - dependent algorithm, for which no time argument is given, to six places of decimals? At 15:07, 10 May 2015 you said The values for the equinox and solstice years were presumably calculated by the same method, but using the true longitude instead of the mean longitude. I get the distinct impression that you don't have the faintest idea what you are talking about. 77.98.244.158 (talk) 12:23, 5 April 2016 (UTC) I agree that neither of us has been able to find the methodology used by Jean Meeus (of whom I had never heard until you objected to his research), but his figures seem to be a modification of the formula derived by Jacques Laskar for the mean tropical year, or of one of the more recent equivalents. He gives a time argument (J2000) for the figure cited. Dbfirs 13:05, 5 April 2016 (UTC)

Mean Solar Days

The current value of the tropical year is about 365.242181 mean solar days (please note that these are slightly different from ephemeris days). By my calculation, this makes the Gregorian calendar accurate to one day in about 3135 years. Have I miscalculated, or are other people comparing apples with pears? The estimation is slightly suspect, of course, because the length of the mean solar day changes slightly over time, but I don't see how the figure in the article is arrived at unless someone is using inappropriate rounding. Dbfirs 07:45, 6 October 2016 (UTC)

I found that the value in the article, 1 day per 3327 years was substantially introduced in this 2005 edit by an editor who does not appear to be active. It was changed from 3300 years to 3327 years by an IP editor recently. I cannot reproduce this value.

I also cannot reproduce Dbfirs' value of 365.242181 mean solar days for the tropical year. Richards (p. 587) gives a value of 365.24217 mean solar days per year, or 365.24219 days if the day is 86,400 SI seconds. This is for 2000, but the formula on page 586 shows the change from 2000 to 2016 is negligible. When I use the value of 365.24217 mean solar days per year, and divide by the tropical year when calculating the error, I get an error of 1 day per 3030 years. Jc3s5h (talk) 13:55, 6 October 2016 (UTC)

References

Richards, E. G. (2013) "Calendars" in S. E. Urban and P. K. Seidelmann Explanatory Supplement to the Astronomical Almanac (3rd ed.). Mill Valley CA: University Science Books. ISBN 978-1-891389-85-0

I must admit that I copied the value from the lead in our article Tropical year and not from an academic reference. Perhaps this article needs changing? Using Richards' value, I agree with your 3030 years. Would you like to make the appropriate changes? Dbfirs 07:30, 7 October 2016 (UTC)

OK. I'll have a look at "Tropical year too. Good catches. Jc3s5h (talk) 13:45, 7 October 2016 (UTC)

Thank you for updating the values. Dbfirs 15:56, 7 October 2016 (UTC)

North Korean Calendar?

In the infobox there is no reference to the North Korean Calendar. PLEASE ADD! 120.151.205.179 (talk) 10:13, 18 August 2015 (UTC)

Yes, it is, under "Juche calendar". --John Maynard Friedman (talk) 19:30, 17 December 2016 (UTC)

References

Semi-protected edit request on 21 December 2016

In the table 'Adoption of Gregorian Calendar', please add Poland/Lithuania. Below part of the code changed to corrected form. Source? Wikipedia in the same paragraph, a few lines above the table. Astymo (talk) 23:06, 21 December 2016 (UTC)

Thank you for your contribution. Unfortunately the text a few lines up is unsourced, so I've tagged it and thus your reasonable request will have to wait until evidence is produced. [By the way, one of our fundamental principles is that Wikipedia must never cite itself. That way madness lies. --John Maynard Friedman (talk) 00:41, 22 December 2016 (UTC)

Ok. Understood. So please see below few links to confirm information about Adoption of Gregorian calendar in Poland-Lithuania, as one of the first states. I hope it will be enough. http://www.webexhibits.org/calendars/year-countries.html https://www.timeanddate.com/calendar/julian-gregorian-switch.html http://www.messagetoeagle.com/the-gregorian-calendar-implemented-on-oct-5-1582/ http://www.almanac.com/fact/first-day-of-conversion-to-gregorian-calendar — Preceding unsigned comment added by Astymo (talk • contribs) 21:07, 3 February 2017 (UTC)

Done Stickee (talk) 00:13, 2 March 2017 (UTC)

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Block quote in lead

In this edit in which Future Perfect at Sunrise restored the correct version of the quote in the lead, the edit summary was "rv, this is what the source actually says (but as an aside, it would be preferable not to use a literal blockquote at all here".

Here is the quote:

Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the year 2000 is.

Personally, I think the lead would flow better if it weren't a block quote. But this statement is possibly the most important thing Wikipedia has to say about the Gregorian calendar, and editors are constantly tinkering with it. Often, the tinkering is wrong. That's why I think making it match a reliable source is more important than how well the lead flows. Jc3s5h (talk) 12:11, 16 May 2017 (UTC)

References

Semi-protected edit request on 5 September 2017

Please revise the link in note 3 from the current line below... The calendar was a refinement to the Julian calendar}}, all that pops up from the reference number [1] is Richards 1998, p. 101.

My proposal is to change this type of reference to {{sfn|Richards|1998|page=101}}. The cited sentence will still look the same to visitors: Before the 1969 revision of the Roman Calendar, the Roman Catholic Church delayed February feasts after the 23rd by one day in leap years; Masses celebrated according to the previous calendar still reflect this delay. and on mouse-over the reference number [2] they will still see Richards 1998, p. 101 but if they hold the mouse over, the pop-up will expand to the full book citation, which to me is a lot more convenient, IMO.

References

Of course it will mean that I will have to reformat the sources to use {{cite book}}, so

• Richards, E. G. (2013). "Calendars". In S. E. Urban and P. K. Seidelmann (eds.), Explanatory Supplement to the Astronomical Almanac 3rd ed. (pp. 585–624). Mill Valley CA: University Science Books. ISBN 978-1-891389-85-6

will become

• Richards, E. G. (2013). "Calendars". In S. E. Urban; P. K. Seidelmann (eds.). Explanatory Supplement to the Astronomical Almanac (3rd ed.). Mill Valley CA: University Science Books. pp. 585–624. ISBN 978-1-891389-85-6.

Any objections? --John Maynard Friedman (talk) 11:47, 4 December 2020 (UTC)

It's OK with me. It looks like there is a book by Richards, and a book chapter by Richards. Also, some of these time & calendar related articles have references to different editions of the same book, so vigilance is needed. Jc3s5h (talk) 13:41, 4 December 2020 (UTC)

Book list

A big change so before I put it live, could someone check it please?

• Barsoum, Ignatius A. (2003). The Scattered Pearls. Piscataway: Georgias Press.
• Blackburn, Bonnie; Holford-Strevens, Leofranc (2003). The Oxford Companion to the Year: An exploration of calendar customs and time-reckoning (corrected reprinting of 1999 ed.). Oxford University Press. ISBN 9780192142313.
• Blegen, Carl W. (25 December 2013) [(n.d.)]. Vogeikoff-Brogan, Natalia (ed.). "An Odd Christmas". From the Archivist's Notebook. Retrieved 1 April 2018.
• Borkowski, K. M. (1991). "The tropical calendar and solar year". Royal Astronomical Soc. of Canada. 85 (3): 21–130. Bibcode:1991JRASC..85..121B.
• Carabias Torres, A. M (2012). Salamanca y la medida del tiempo (in Spanish). Salamanca: Ediciones Universidad de Salamanca.
• Coyne, G. V.; Hoskin, M. A.; Pedersen, O., eds. (1983). Gregorian Reform of the Calendar. Vatican Conference to Commemorate its 400th Anniversary, 1582–1982. Vatican City: Pontifical Academy of Sciences, Vatican Observatory (Pontificia Academia Scientarum, Specola Vaticana).
• Dershowitz, D.; Reingold, E. M (2008). Calendrical Calculations (3rd ed.). Cambridge: Cambridge University Press.
• Duncan, D. E (1999). Calendar: Humanity's Epic Struggle To Determine A True And Accurate Year. HarperCollins. ISBN 9780380793242.
• Gregory XIII (1582). Inter Gravissimas [Amongst the most serious tasks of our pastoral office]. Translated by Wikisource.
• Meeus, J.; Savoie, D. (1992). "The history of the tropical year". Journal of the British Astronomical Association. 102 (1): 40–42.
• Morrison, L. V.; Stephenson, F. R. (2004). "Historical values of the Earth's clock error ΔT and the calculation of eclipses". Journal for the History of Astronomy. 35, part 3 (120): 327–336.
• Moyer, Gordon (May 1982). "The Gregorian Calendar". Scientific American. Vol. 246, no. 5. pp. 144–152.
• Moyer, Gordon (1983). Coyne, G. V.; Hoskin, M. A.; Pedersen, O. (eds.). Aloisius Lilius and the Compendium Novae Rationis Restituendi Kalendarium. Gregorian Reform of the Calendar: Proceedings of the Vatican Conference to Commemorate its 400th Anniversary. Vatican City: Pontifical Academy of Sciences, Specolo Vaticano. pp. 171–188.
• Pattie, T.S. (1976). "An unexpected effect of the change in calendar in 1752" (PDF). British Library Journal.
• Pedersen, O (1983). Coyne, G. V.; Hoskin, M. A.; Pedersen, O. (eds.). The Ecclesiastical Calendar and the Life of the Church". Gregorian Reform of the Calendar: Proceedings of the Vatican Conference to Commemorate its 400th Anniversary. Vatican City: Pontifical Academy of Sciences, Specolo Vaticano. pp. 17–74.
• Richards, E. G. (1998). Mapping Time: The Calendar and its History. Oxford University Press.
• Richards, E. G. (2013). "Calendars". In Urban, S. E.; Seidelmann, P. K. (eds.). Explanatory Supplement to the Astronomical Almanac (3rd ed.). Mill Valley CA: University Science Books. pp. 585–624. ISBN 978-1-891389-85-6.
• Seidelmann, P. K., ed. (1992). Explanatory Supplement to the Astronomical Almanac (2nd ed.). Sausalito, CA: University Science Books.
• Swerdlow, N. M. (1986). "The Length of the Year in the Original Proposal for the Gregorian Calendar". Journal for the History of Astronomy. 17 (49): 109–118.
• Walker, G. W. (June 1945). "Easter Intervals". Popular Astronomy. Vol. 53, no. 6. pp. 162–178, 218–232.
• Ziggelaar, A. (1983). Coyne, G. V.; Hoskin, M. A.; Pedersen, O. (eds.). The Papal Bull of 1582 Promulgating a Reform of the Calendar. Gregorian Reform of the Calendar: Proceedings of the Vatican Conference to Commemorate its 400th Anniversary. Vatican City: Pontifical Academy of Sciences, Specolo Vaticano. pp. 201–239.

• I have copied this revision to live. --John Maynard Friedman (talk) 12:34, 16 December 2020 (UTC)

Book list markup

@John Maynard Friedman:. Your recent edits suggest you think the following would not work: Scientific American is a great magazine.{{sfn | Moyer | 1982}}

{{cite magazine|author-last1=Moyer |author-first1= Gordon | issue= 5 | volume = 246|date = May 1982 | title= The Gregorian Calendar | magazine=Scientific American | pages=144–152}}

But it does work. The templates are able to extract the 1982 from the date and match it up with the 1982 from the sfn template. Jc3s5h (talk) 19:18, 15 December 2020 (UTC)

Thanks, that's good news. I couldn't find anything at {{sfn}} or {{cite}} to say it did so I didn't bother to try. Oh me of little faith. I will change it back. Did you have time to check any others? One item that worried me is that Worldcat is giving the same ISBN for all editions of the The Oxford companion to the year, but I suppose the change from ISBN-10 to ISBN-13 just exposed a pre-existing issue, it didn't create it. --John Maynard Friedman (talk) 19:36, 15 December 2020 (UTC)

 Done --John Maynard Friedman (talk) 12:40, 16 December 2020 (UTC)

I checked the following book, which I own:

Cite book comparison

Wikitext	{{cite book|author-first1=Bonnie|author-first2=Leofranc|author-last1=Blackburn|author-last2=Holford-Strevens|isbn=9780192142313|publisher=Oxford University Press|title=The Oxford Companion to the Year|year=1999}}
Live	Blackburn, Bonnie; Holford-Strevens, Leofranc (1999). The Oxford Companion to the Year. Oxford University Press. ISBN 9780192142313.

.

I checked that it sort of supports all the claims in the article, more on that later. The one I have was reprinted with corrections in 2003, so I would write the citation thus

Cite book comparison

Wikitext	{{cite book|author-first1=Bonnie|author-first2=Leofranc|author-last1=Blackburn|author-last2=Holford-Strevens|edition=corrected reprinting of 1999|isbn=9780192142313|publisher=Oxford University Press|title=The Oxford Companion to the Year|year=2003}}
Live	Blackburn, Bonnie; Holford-Strevens, Leofranc (2003). The Oxford Companion to the Year (corrected reprinting of 1999 ed.). Oxford University Press. ISBN 9780192142313.

.

World cat seems to say that ISBN goes with the 2003 corrected reprinting, and agrees with what is printed on page iv of mine.

In the article, the whole section "Difference between Gregorian and Julian calendar dates" is suspect because it describes one calculation, but supports it with more than one source (one of them is Blackburn & Holford-Strevens); who is to say the calculations in the two sources are compatible? The section extends the calculation before AD 1, but the book only gives dates in the 2nd and 3rd millennium as examples. Jc3s5h (talk) 20:37, 15 December 2020 (UTC)

 Done , though not identically. --John Maynard Friedman (talk) 12:40, 16 December 2020 (UTC)

I want to stick with tunnel vision for the moment, and just update the citation style. The question you raise is a valid one but best I leave it to you to resolve. (I have doubts about extending the proleptic Gregorian before 325 but I definitely think that we should not facilitate extension before the epoch, that way madness lies. --John Maynard Friedman (talk) 21:01, 15 December 2020 (UTC)

I have copied the list to live. Feel free to just revert if you see anything that needs further correcting because the version above is up to date and can more easily be revised and recopied to live when done. --John Maynard Friedman (talk) 12:40, 16 December 2020 (UTC)