Gilbert, Martin
Routledge, 1994
Buku Teks
Semmler, Clement
University of Queensland Press [distributed by International Scholarly Book Services, 1972
Buku Teks SO
edited by Ken Goodwin and Alan Lawson
Macmillan, 1990
Buku Teks
Fredericks, Pierce
E.P. Dutton, 1960
Buku Teks
Fischer, Fritz
W.W. Norton & Company, 1967
Buku Teks