Johnson, Robert
PWS-Kent, 1984
Buku Teks SO
Erricker, B.C.
Hodder and Stoughton, 1981
Buku Teks SO
Freund, John E.
Pearson Prentice Hall, 2007
Buku Teks SO
Freund, John E.
Pearson Education, 2007
Multimedia
Freund, John E.
Prentice-Hall, 1980
Buku Teks