Nielsen, Waldemar A., author
Atheneum, 1966
Buku Teks
Murdock, George Peter, author
McGraw-Hill, 1959
Buku Teks
Murdock, George Peter, author
McGraw-Hill, 1959
Buku Teks
edited by Phillis M. Martin and Patrick O'Meara
Indiana University Press, 1995
Buku Teks
edited by C. Grove Haines
John Hopkins Press, 1956
Buku Teks