A citation manager:
Some have additional features, including PDF annotation, database searching, finding full text, and social networking.
Learn more on the HSLS Citation Manager page.
Using a citation manager will really help with organizing your research and creating citations and bibliographies. Pick your citation manager before you start your research process and it will make life much easier.
When choosing a citation manager, you might consider...
And most importantly, which one do you like the best?
Note: All of these citation managers are interoperable, so you can always switch to a different one.