edited by David Collier
Princeton University Press, 1979
Buku Teks
Pierson, William W., author
D. Van Nostrand, 1953
Buku Teks
Pendle, George, author
Penguin Books, 1973
Buku Teks
Rippy, J. Fred, author
University of Michigan Press, 1958
Buku Teks
edited by Philip M. Hauser
Unesco, 1961
Buku Teks