Craven, Paul R.
Dickenson Publishing, 1968
Buku Teks SO
Tyabji, Kamila
Stevens & Sons, 1949
Buku Klasik
Peeters, Benoît, 1956-
Polity Press, 2013
Buku Teks SO
Berg, A.Scott
Riverhead Books, 1989
Buku Teks
Josephson, Matthew
McGraw-Hill, 1959
Buku Teks SO