  This study compares and analyses publication and document types in the
following bibliographic databases: OpenAlex, Scopus, Web of Science, Semantic
Scholar and PubMed. The results demonstrate that typologies can differ
considerably between individual database providers. Moreover, the distinction
between research and non-research texts, which is required to identify relevant
documents for bibliometric analysis, can vary depending on the data source
because publications are classified differently in the respective databases.
The focus of this study, in addition to the cross-database comparison, is
primarily on the coverage and analysis of the publication and document types
contained in OpenAlex, as OpenAlex is becoming increasingly important as a free
alternative to established proprietary providers for bibliometric analyses at
libraries and universities.
