Cirovic, Michael M
Reston Publishing Company, 1979
Buku Teks
McGraw-Hill Book Comp., 1971
Buku Teks
Clyde F. Coombs, editor-in-chief
McGraw-Hill, 1972
Buku Referensi
Bialko, M.
Prentice-Hall, 1995
Buku Teks
Bethune, James D., author
Prentice-Hall, 1980
Buku Teks