editor, Terrell Croft [and others]
McGraw-Hill, 1981
Buku Referensi
Radin, Max
St Paul Minn, 1936
Buku Teks
edited by Gary Hoover, Alta Campbell, Patrick Spain
The Reference Press, 1991
Buku Referensi
Whitford, Harold C.
Regents Publishing, 1973
Buku Teks
Guthrie, L.O., author
Macmillan, 1956
Buku Teks