Young, Cynthia Y.
John Wiley & Sons, Inc, 2007
Buku Teks SO
Marcus, Marvin
Houghton Mifflin, 1970
Buku Teks SO
Cameron, Edward A.
Holt, Rinehart and Winston, 1965
Buku Teks SO
Barnett, Raymond A.
McGraw-Hill, 2001
Buku Teks SO
Vance, Elbridge P.
Addison-Wesley, 1962
Buku Teks SO