**Find out what style guide is required/recommended for your thesis.
You can save citations in a database and these tools will automatically format your citations into the style you need (ex. MLA, APA, Turabian,...). Zotero is an add-on to Firefox and with it you can directly download citations from your browser. There is also a standalone version for Chrome or Safari. In addition, many databases allow you to directly export citations to Refworks and Zotero, using their save/export function.
See the Middlebury Style and Citation Guide for information and help with Refworks, Zotero, and other tools as well as print style guides available in the libraries (MLA, APA, Chicago, Turabian, etc.).