Woodby, Sylvia
Westview Press, 1988
Buku Teks
edited Steven L. Spiegel
St. Martin's Press, 1981
Buku Teks
The John Hopkins University Press, 1979
Buku Teks
Smith, Joseph
Blackwell Publishers, 1998
Buku Teks
Friedmann, Wolfgang, 1907-1972, author
Vorkonk-Van Hoeve, 1976
Buku Teks