Particular comment needs to be made of the publication types that were included in the database.
Six publication types are identified in our database, namely, books, book chapters, conference papers, journal articles, manuscripts and theses.
For the economics publications we restricted our analysis to the publication types: 'Articles,' 'Reviews' and 'Proceedings Paper'.
Moreover, the related articles function was also used to broaden the search, and all studies, abstracts were reviewed without restriction to regions, publication types, or languages.
The terms were cross-referenced to exclude animal research and non-research publication types, and to include only papers in English and with abstracts, resulting in the exclusion of one reference.
Records can be assigned one or more publication types.
For 2008 MeSH there was a major revision of Publication Types (PT) and the phrase "as Topic" was added [18].
As a tool for additional analysis of parts of the results we extracted the publication types assigned to the records.
For MeSH 2008 there was a major revision of Publication Types (PT) and the phrase "as Topic" was added [14].
We constructed a Microsoft Access database for the analysis that contained the complete Medline citation for each article, including author names, publication types, and MeSH terms.
PubMed offers even more ' publication types'.
