These sites will help you to cite most common sources in a number of citation styles.
Citation managers are software or web tools that allow users to collect, organize, read and take notes on articles, books, or other research resources. There is typically a web browser plugin that allows users to capture information about a resource with just a few clicks and it's stored in the citation manager.
Later on, users can read and take notes on these resources, organize them into folders and by using tags.
When it comes time to write, the citation manager is is able to create in-text citations, properly formatted according to which ever style the user chooses. The citation manager can also then be used to create a bibliography or works cited section, again properly formatted.