http://books.google.de/books?id=jhAqhj5Jr54C&pg=PA2
http://books.google.de/books?id=zhsAAAAAMAAJ&pg=PA477
10.1007/s11167-005-0037-1
http://www.ingentaconnect.com/content/tandf/nzvj/1974/00000022/00000006/art00001#expand/collapse
Berzelius’ Discovery of Selenium by Jan Trofast http://www.iupac.org/publications/ci/2011/3305/sept11.pdf#page=18
10.1007/978-1-4614-1025-6_1
10.1007/0-387-33827-6_1