This guide includes a variety of resources to help with citing sources. The citation format of your research paper depends on your professor's assignment. You should know the required citation style before you construct your bibliography.
A Manual for Writers of Research Papers, Theses, and Dissertations by 
Publication Manual of the American Psychological Association by Many citation formats use Digital Object Identifiers (doi) in the citatoins. Here is a resource to help you find the doi for you citation.
