Artikel Jurnal
[consultant editors, Christopher M. Brown, D.A. Hogg, D.F. Kelly]
Oxford University Press, 1988
Buku Referensi
Warner, Jill Diana
Elsevier, 2005
Multimedia
Engelking, Larry R.
Elsevier, 2011
Buku Teks SO
Engelking, Larry R.
Elsevier, 2015
Buku Teks SO