Frederick A. Praeger, 1969
Buku Teks
edited by Harvey G. Kebschull
Appleton-Century-Crofts , 1968
Buku Teks
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