Zotero is a citation management tool that's free to download and that offers 300 MB of storage free of charge; additional storage is available for a yearly fee.
Zotero is available for Mac, Windows, and Linux and is available in desktop and web versions.
In addition to downloading Zotero, it is recommended that you install the Zotero Connector for whichever browser(s) you use regularly, since doing this will allow you to save references to Zotero from your browser. Connectors are available for Chrome, Firefox, and Safari.
Note that the UMGC Library does not provide support for Zotero; please see Zotero's help page if you need help with using this tool.