Northam, Ray M., author
John Wiley & Sons, 1979
Buku Teks
Quinn, James A., author
American Book Company, 1955
Buku Teks
s.l. s.n. c.1979,
Buku Teks
Gist, Noel P., author
Harper & Row , 1974
Buku Teks
Abrahamson, Mark, author
Prentice-Hall, 1980
Buku Teks