Barnes & Noble Books, 1969
Buku Teks
by Ronald Freedman [and others]; with a chapter by Guy E. Swanson
Henry Holt, 1952
Buku Teks
Goode, William J.
Tata McGraw-Hill, 1977
Buku Teks
Cuber, John F.
Buku Teks
Schrag, Clarence C., author
Harper & Row, 1963
Buku Teks