Most databases available to Yale users are paid for by Yale Library subscriptions, so that you don't have to pay. When you are off-campus, these are still accessible to you, through Lean Library Access, EZProxy, or VPN. See the page linked below for more information.
What is Scholarly Literature?
There are three major citation styles used in the humanities, social sciences, and some scientific disciplines. Consult one of the following official style manuals :