You and several others have recommended Mendeley but I personally wouldn't touch it with a ten-foot pole. It's a nice system but 1) it's proprietary, and 2) it's owned by Elsevier, a company notorious for its shady business practices:

- https://politics.slashdot.org/story/12/03/19/2220208/boycott...

- https://science.slashdot.org/story/13/12/06/1945224/elsevier...

- https://science.slashdot.org/story/15/11/02/1323258/all-edit...

Personally, I very much prefer Zotero but here's a great comparison of both software http://www.library.yorku.ca/web/research-learn/citations/zot...