Barrat, David, author
Routledge, 1994
Buku Teks
Schaefer, Richard T, author
McGraw-Hill , 1989
Buku Teks
Goodyear Publishing, 1972
Buku Teks
Gelles, Richard J., author
McGraw-Hill College , 1999
Buku Teks
Currier, Glenn
Harcourt, college Pub., 1997
Buku Teks