Wilcox, Glade
Holt, Rinehart and winston, 1960
Buku Teks
Simpson, A.
Macmillan, 1976
Buku Teks
Schuler, Charles A., author
McGraw-Hill, 2013
Buku Teks
Olsen, George H., author
Prentice-Hall, 1980
Buku Referensi
Brophy, James J., author
McGraw-Hill, 1977
Buku Teks