Check out Mendeley (
<a href="https://www.mendeley.com/">website here</a>
).
- It’s free (with options to upgrade).
- It’s cross-platform (Windows, OSX, and Linux).
- You can view and annotate PDFs.
- You can import citations from PDFs
- You can insert citations into Word, etc.
I don’t work for them, but I’ve been using them for years, and I’m a huge fan.