Harvard style uses an author-date system for references and is similar to APA style. There are two components of Harvard style: an in-text citation that identifies the author, date and page number of your source and a more detailed entry included in a reference list at the end of your paper.
Zotero [zoh-TAIR-oh] is a free Firefox, Chrome, & Safari extension that helps you collect, manage, and cite your research sources. It lives within your web browser. Zotero allows you to automatically import references and full text documents from online catalogs (like the library catalog and WorldCat) and databases, as well as open websites like newspaper sites, blogs, even Flickr and YouTube. You can easily create automatically formatted bibliographies and in-text citations from your Zotero library of references.