Facts on file, 1989
Buku Teks
Hewes, Gordon W.
Burgess Pub. Co., 1973
Buku Teks
Weidenreich, Franz, 1873-1948
The University of Chicago Press , 1946
Buku Teks
Botha, Rudolf P, author
Cambridge University Press, 2016
Buku Teks
Simpson, George Gaylord, author
Yale University Press, 1952
Buku Teks