Zotero
Zotero is a free tool that helps you collect, organize, and cite resources. You can even sync these resources with Microsoft Word or Google Docs to easily add in-text citations and bibliographies to your papers.
Zoterobib
Do you just want to create a quick citation or bibliography? Try zoterobib. Note: You won't be able to collect and save your resources, or sync them with your Word or Google doc. For complete functionality, you'll want to download the full Zotero.
Using Zotero on a Public Computer
You can use Zotero on a computer that is not your personal device by logging into your Zotero Cloud Account. You can create an account at Zotero.org. Click near the top right where it says Log In.