Gagne, Robert M.
Holt, Rinehart and Winston, 1970
Buku Teks
Wilson, John A. R., author
McGraw-Hill, 1974
Buku Teks
Harper & Row , 1971
Buku Teks
Biehler, Robert F.
Houghton Miffiln, [date of publication not identified]
Buku Teks
De Cecco, John P.
Prentice-Hall, 1974
Buku Teks