Test cases:
- The International Seismological Centre will have authoritative data for this event in due course.[sb]
- The International Seismological Centre has data and a bibliography for this event {389808).[sb]
- The International Seismological Centre has data and a bibliography for this event {-389808).[sb] <- Negative.
....
- The International Seismological Centre will have authoritative data for this event in due course.