Sage, 2014
Buku Teks SO
edited by Anthony Gale, Michael W. Eysenck
John Wiley & Sons, 1992
Buku Referensi
McMahon, Linnet
Routledge, 1992
Buku Referensi
edited by Diane Elizabeth Waller and Andrea Gilroy
Open University Press, 1992
Buku Referensi
edited by Samuel M. Turner, Karen S. Calhoun, Henry E. Adams
John Wiley & Sons, 1992
Buku Referensi