A comparative study of citations to chemical encyclopedias in scholarly articles: Kirk-Othmer Encyclopedia of Chemical Technology and Ullmann’s Encyclopedia of Industrial Chemistry

Subject encyclopedias have long been regarded as authoritative reference works that contain credible and reliable information on a subject area or discipline for use by scholars and researchers. In the digital age, when subject-specific information is readily accessible online for free or through a subscription-based resource, researchers may no longer rely on standard reference sources such as subject encyclopedias. To determine whether subject encyclopedias are used in research, a citation analysis study was conducted using two of the best-known subject encyclopedias relevant to chemists and chemical engineers: the Kirk-Othmer Encyclopedia of Chemical Technology and Ullmann’s Encyclopedia of Industrial Chemistry. Citations to each encyclopedia were obtained from the Science Citation Index Expanded in Web of Science (WoS) from 2000 to 2015 (inclusive) and compared by document type. Article citations to these encyclopedias were compared by year, journal, country of publication, organizational affiliations, and WoS subject category. Over the sixteen-year period, citations to both encyclopedias have doubled from 943 to 1876 peer-reviewed articles. The study supports the view that such long-standing reference sources are still needed for research and valued by the scientific community despite the availability of online resources. The study used VOSviewer to analyze and compare the key terms in the title and abstract of all articles citing each encyclopedia. This analysis revealed sub-disciplinary differences in the use of the two encyclopedias.