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
Molnos, Angela
Weltforum Verlag, 1968
Buku Teks
Caminos, Horacio, author
MIT Press, 1980
Buku Teks