Zotero is a powerful, easy-to-use research tool that helps you gather, organize, and analyze sources and then share the results of your research. Developed by George Mason University
License: Open Source
Zotero is primarily a reference management tool that excels in citation management and organization, making it ideal for academic research. In contrast, Polar combines reference management with advanced PDF annotation features, catering to users looking for a more integrated reading and note-taking experience.