: You get access to all features, including syncing across devices and advanced PDF annotation.
If you are a student, researcher, or faculty member, you likely have access to EndNote for through your institution. endnote-x9-3-3-full-version-free-download
If you don't need the heavy-duty desktop features of the X9 or 21 versions, is a free, web-based version. : You get access to all features, including
: A free reference manager and academic social network that is excellent for managing PDFs. or faculty member
: Most university libraries pay for site licenses. Search your library’s website for "EndNote" or "Reference Management Software."
: Store up to 50,000 references and 2GB of attachments.
: Highly recommended, open-source, and has a powerful browser extension for saving sources.