Leitch, George
Victoria University Press, 1990
Buku Teks
Weber, Max, 1864-1920, author
Macmillan, 1964
Buku Teks
Oxford University Press, 1992
Buku Teks
Academic Press, 1992
Buku Teks
edited by Michael J. Novacek and Quentin D. Wheeler
Columbia Univerdity Press, 1992
Buku Teks