Keenan, George F., author
Harper & Row, 1964
Buku Teks
Hinton, Harold C., author
Houghton Miffiln, 1966
Buku Teks
Lampert, Hope, author
Atheneum, 1986
Buku Teks
Fowkes, Ben, author
Palgrave, 2002
Buku Teks
Borkenau, Franz
University of Michigan Press, 1962
Buku Teks