edited by H. Thompson Prout, Douglas T. Brown
John Wiley & Sons, 2007
Buku Teks SO
London: Tiger Books International, 1994,
Buku Referensi
Austad, Carol Shaw
Jossey-Bass Publishers, 1996
Buku Teks SO
Oxford University Press, 1990
Buku Referensi
Lacey, Alan Robert
Routledge, 1986
Buku Referensi