Citation format

This is called a parenthetical citation.

Eg., Natural selection (Darwin 1860) works by...

If you quote, or cite specific information, include the page number.

Eg., "The most successful species is the most adaptable," (Darwin 1872, p. 206), or
Darwin noted that a group of finches developed different beaks (Darwin 1860, pp 164-70).

If you cite multiple authors on a given point, list them in alphabetical order.

Eg., Primitive peoples have an almost childlike belief in magic (Levy-Bruhl 1956 et alia, Levy-Strauss 1965, 1966)

Note the use above of et alia, suggesting that the author has made the same statement repeatedly. The use of multiple dates on the second citation says that Levy-Strauss' argument for this can be found in those two places.

If you are citing the same author repeatedly without intervening reference to a different author, you can use ibid.

Eg. Deleuze is the greatest philosopher ever (King 2012). I agree with King on this point, but I don't agree with his contention Hegel sucks the big one (ibid, pp 212-214).

Where you are referring to a single work by an author throughout, you may use op.

Eg, [Given that you have made earlier reference to Darwin 1860] This argument does not hold up, for, as Darwin (op. cit., p 308) says...

Where you use more than one work by the same author, but those works were published in the same year, use a letter following the date.

Eg., (Horton 1967a) (Horton 1967b)

Bibliography for this citation system

I should like you to use the following format for bibliographic entries.

Horton, R.
1967a "Science and African Traditional Thought, Part I," in Africa, Vol 8/4, pages 214-257.

1967b "Science and African Traditional Thought, Part II," in Africa,
Vol 8/5, pages 113-139.

1980 My Life in Science, London: Rutledge.

Notice that entries are done chronologically, and that the last is a (fictitious) book entry, whereas the other two are...