Marks, John, author
Heinemann, 1983
Buku Teks
Vasta, Ross, author
John Wiley & Sons, 1999
Buku Teks
Ramsey, William L., author
Holt, Rinehart and Winston, 1961
Buku Teks
Goldschlager, Les, author
Prentice-Hall, 1982
Buku Teks
Bierstedt, Robert, author
McGraw-Hill, 1964
Buku Teks