edited by David E. Long and Bernard Reich
Westview Press, 1986
Buku Teks SO
Halpern, Manfred
Princeton University Press, 1963
Buku Teks SO
Harari, Maurice
Prentice-Hall, 1962
Buku Teks
edited by Muneera Salem-Murdock and Michael M. Horowitz, with Monica Sella
Westview Press, 1990
Buku Teks SO
Deegan, Heather
Routledge, 1996
Buku Teks SO