There are several reasons why we cite our sources:
To cite a source you will create a short reference, which you will ultimately list on your bibliography. References are made up of common elements that provide your readers with the information that they need to track down sources. The most common elements are:
This is an example of how a reference to a secondary source might look in the Chicago style:
Snow, Dean. "Sexual Dimorphism in European Upper Paleolithic Cave Art." American Antiquity 78, no. 4 (2013): 746-61.
This is an example of how a reference to a primary source in print might look in the Chicago style:
Weiner, Lawrence. "And Then Unintended As," 1972. In Artists Talk, ed. Peggy Gale. Halifax, Nova Scotia: Press of the Nova Scotia College of Art and Design, 2004.