Zotero is a free, open-source citation management software program with plug-ins for internet browsers and word processors. If you have a lot of references, it can help you track and organize your sources, collect bibliographic information with one click, and automatically generate in-text citations and entire bibliographies in many styles.
If you are using Zotero on a Mac, the "Insert Citation" feature for Microsoft Word is available in the script menu:
Here are a couple of useful resources that may help you organize your sources and structure your literature review: