Zotero

• Helps researchers to collect, organize, cite, and share sources
   
• Is open source software with 300 MB of storage for free
   
• Works with Windows, Mac, and Linux systems

Although Zotero automates many processes for you, the output isn't always 100% correct. You will need to be familiar enough with your style so that you can verify and fix the formatting in Zotero before you use the citations in your document.

• How to verify formatting
• How to fix formatting 

When on networked computer, you can add and edit items in your online zotero.org library using the Bookmarklet, but you cannot cite in Word or preview the citation. Those functions are available only on the desktop application.