Mendeley
Mendeley is a free reference manager and an academic social network. Manage your research, showcase your work, connect and collaborate with over five million researchers worldwide.
Zotero
Zotero is the only research tool that automatically senses content in your web browser, allowing you to add it to your personal library with a single click. Whether you’re searching for a preprint on arXiv.org, a journal article from JSTOR, a news story from the New York Times, or a book from your university library catalog, Zotero has you covered with support for thousands of sites.