Google Scholar

Google Scholar: One simple change can connect Google Scholar with links to the full-text of articles that the library can provide. Use the Connecting Google Scholar with Harvard Library page for instructions. 

Google Scholar is also helpful for seeing how many times articles are cited after they are published, using the "Cited by" hyperlink, which will also bring up a list of those articles.

Zotero

Zotero is a free, open source citation management tool that makes the process of collecting and organizing citations, incorporating them into your paper, and creating a bibliography or works cited page, stress-free and nearly effortless.

It's worth the small investment of time to learn Zotero. A good guide, produced by Harvard librarians, is available here: http://guides.library.harvard.edu/zotero