Bierstedt, Robert, author
McGraw-Hill, 1974
Buku Teks
Castells, Manuel, author
Macmillan, 1978
Buku Teks SO
edited by Saul Patai
John Wiley & Sons, 1975
Buku Teks
Masson, VeNeta
Springer Publ ., 1981
Buku Teks
edited by David N. Balaam and Michael J. Carey
Allanheld, Osmun, 1981
Buku Teks