How was Century of Science compiled and what is included?
By examing which articles from 1945-2004 in WoS was highly cited 200.000 journal items were found – articles, reports, editorials, reviews and commentaries. By identifying which items that had at least 50 citations to them a collection of 2.000 journals were identified. By further examinations described in the document “The story behind the data” [PDF], a core collection of 262 important journals were selected and indexed. Here’s the list of journal coverage in Century of Science.