Atkinson, Paul
Routledge, 1994
Buku Teks
Antonius C.G.M. Robben, Jeffrey A. Sluka.
Wiley-Blackwell, 2012
Buku Teks
Jenks, Albert Ernest
American Association, 1937
Buku Teks
Murphy, Robert F.
George Allen and Unwin, 1972
Buku Teks
Harris, Marvin, 1927-2001
Routledge & Kegan Paul LTD, 1969
Buku Teks