Citation managers such as EndNote Basic (aka EndNote Online), EndNote 20, Zotero, and Mendeley are tools for managing your citations. Among other things, citation managers can help you to:
The "best" citation manager will depend on the functions you're looking for in a citation manager.
Each citation manager shares some of the same, basic functions, including, among other things, the ability to:
However, there are functions that only some citation managers have. The UW Libraries' Comparison Chart provides a comprehensive comparison of the available functions in EndNote Basic, EndNote 20, Zotero, and Mendeley.
Important Note: If you are co-writing a paper as a team (i.e., more than one person will be adding citations to a single document), it is preferable that all team members use the same citation manager for the project.