The citation identifies the publication in which the idea, the excerpt, etc., was obtained and indicates its exact location in the source. When the quote is used in accordance with a list of references it should contain sufficient data to ensure the exact match between that quote and the reference document.
Citations are made to support a hypothesis, to sustain an idea or to illustrate an argument. Its main function is to provide the reader with the necessary data so that he can prove the veracity of the information and allow for further development.
When citations are made, the cited bibliography should be listed at the end, in an alphabetically or numerically manner, according to the way the quote was made.