Murdock, George Peter, author
McGraw-Hill, 1959
Buku Teks
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
Carter, Gwendolen M., author
Frederick A. Praeger, 1961
Buku Teks