The objective of this study is to investigate the references used in the WGI contribution to AR6, Climate Change 2021: The Physical Science Basis. The first part gives an overview of the references and describes the use, sources, dates and languages of the citations. A second part is dedicated to the geographical aspects of the references and presents their countries and institutions of origin. A third part deals with the themes addressed by the references and finally, a last part focuses on the variety of authors and their links with the references. This analysis is based on the data associated with the references in the report, some fields of which are supplemented by data collected online. Details of the data used are given in each section with a reference to the supplementary materials where necessary.