Stewart, Kilton
W.W. Norton & Company, 1954
Buku Teks
BBC Worldwide Limited, 2004
Multimedia
Rolvaag, O.E., author
Harper & Row, 1965
Buku Teks
Weidenreich, Franz, 1873-1948
The University of Chicago Press , 1946
Buku Teks
Follett, ken, author
Esensi, 2010
Buku Teks