Thomas, David A.
Allyn and Bacon, 1991
Buku Teks SO
Beckmann, Sybilla
Pearson Addison Wesley, 2008
Buku Teks SO
Garstens, Helen L.
Macmillan, 1969
Buku Teks SO
Phares Odaffer, Randall Charles, Thomas Cooney, John Dossey, Jane Schielack
Pearson Addison Wesley, 2008
Buku Teks SO
Solomon, R.C.
London DP Publications 1993,
Buku Teks