According to the OECD Glossary of Statistical Terms, "bibliometrics is a statistical analysis of books, articles, or other publications. Bibliometric analysis use data on numbers and authors of scientific publications and on articles and the citations therein (and in patents) to measure the 'output' of individuals/research teams, institutions, and countries, to identify national and international networks, and to map the development of new (multi-disciplinary) fields of science and technology."
The premise of co-citation analysis studies is that if two documents are cited together by a third document, it likely indicates some structural relationship between the two documents.
The analyses and visualizations included below were created with VOSviewer, a freely available software created by Nees Jan van Eck and Ludo Waltman who are researchers at the Centre for Science and Technology Studies (CWTS) of Leiden University in the Netherlands.