A citation is made of parts, each part indicating specific information about the source (author, title, page no., etc… - depends on the resource). This bibliographic information together makes up a complete full citation. That's why a reference list is sometimes also called a 'Bibliography'.
A full citation will give the reader a clue as to the type of resource being described (chapter in a book, electronic journal article, thesis, etc.). The below example follows the APA style and is a journal article in print format: