Barney, Jay B.
Houghton Miffiln, 1992
Buku Teks
Light, H.R.
Pitman , 1974
Buku Teks
Williamson, Oliver E., author
Markham, 1967
Buku Teks
Champion, Dean J., author
McGraw-Hill , 1975
Buku Teks
edited by Kristian S. Palda
Prentice-Hall, 1973
Buku Teks