Johnson, James H.
Allyn and Bacon, 1997
Buku Teks SO
Ross, Alan O.
John Wiley & Sons, 1981
Buku Teks SO
Nahm, Sheena
Maryland : Lexington Books, 2014
Buku Teks SO
Semrud-Clikeman, Margaret
Allyn and Bacon, 1995
Buku Teks SO
Bateman, Anthony
Brunner-Routledge, 2003
Buku Teks SO