When reading published sources, it is important to be able to understand citations. A citation or reference provides all the essential elements of information about the source to enable anyone to track it down. This includes the author, title, source and date of publication.
The ability to interpret citations or references to various sources of information is a fundamental research skill. In order to be able to locate an item, you need to be able to determine what type of source the item is. A partial list of types of sources would include: