Variations on the Author-date system
As with footnotes, there are many variations on the format of parenthetical citations and reference list entries given here. It does not matter which system you choose, as long as you are consistent and maintain the same format throughout your work.
There are many different styles of parenthetical referencing currently in use. The Modern Language Association of America (MLA), for example, recommends only including the author's name and a page reference if necessary in a citation, and omitting the date.
Here are some variations. Note the lack of 'p.' preceding the page references.
(Jones 2004, 89)
(Jones, 2004: 89)
Reference list entries
There is a similar diversity in the format of reference list entries in books and articles written using the author-date system. Here are some examples.
Jones, R. (2004), Giant insects of the Cretaceous, London.
Jones, R. (2004), Giant insects of the Cretaceous (London).
Jones, R. 2004 Giant insects of the Cretaceous London.
Jones, R. 2004. Giant insects of the Cretaceous (London: Smith)