Pocock, Douglas
Macmillan, 1978
Buku Teks SO
Mercer, Charles
Penguin Books, 1975
Buku Teks SO
Gallion, Arthur B.
D. Van Nostrand, 1975
Buku Teks
Getis, Arthur
Macmillan, 1985
Buku Teks
edited by D. T. Herbert and R. J. Johnston
John Wiley & Sons, 1981
Buku Teks