Frank, Howard
Addison-Wesley, 1971
Buku Teks
Sherman, Kenneth, author
Reston Publishing company, 1981
Buku Teks
Doll, Dixon R., author
John Wiley & Sons, 1978
Buku Teks
Housley, Trevor
Prentice-Hall, 1987
Buku Teks
McGraw-Hill Publications, 1983
Buku Teks