Owens, Edgar
Lixington Books, 1972
Buku Teks
Owens, Robert G.
Prentice Hall Inc., 1991
Buku Teks
Burns, James McGregor, author
Prentice-Hall, 1972
Buku Teks
Burns, James McGregor, author
Prentice-Hall, 1989
Buku Teks
Emden, Cecil S.
At The Clarendon Press, 1956
Buku Teks