Kraus, Michael, author
University of Oklahoma Press, 1953
Buku Teks
Smelser, Marshall, author
Barnes & Noble, 1873
Buku Teks
Krooss, Herman Edward, 1912-1975, author
Prentice-Hall, 1972
Buku Teks
Robertson, Ross M., author
Harcourt, Brace & World, 1964
Buku Teks
Graebner, Norman A., author
McGraw-Hill, 1975
Buku Teks