Murdock, George Peter, author
McGraw-Hill, 1959
Buku Teks
Nielsen, Waldemar A., author
Atheneum, 1966
Buku Teks
edited by Phillis M. Martin and Patrick O'Meara
Indiana University Press, 1995
Buku Teks
Buku Teks
Creighton, Donald, author
Macmillan, 1952-1955
Buku Teks