Cambridge University Press, 1979
Buku Teks
Lloyd, P.C
Frederick A. Praeger, 1968
Buku Teks
Kitzinger, Uwe W., author
Clarendon Press, 1960
Buku Teks
Nye, Russel B.
Michigan State University Press, 1959
Buku Teks
Dodge, Dorothy, author
D. Van Nostrand, 1966
Buku Teks