Denning, author
Llewellyn Publication, 2008
Buku Teks
Gawain, Shakti, author
Whatever Publisher, 2002
Buku Teks
Webster, Richard, author
Llewellyn Publication, 2009
Buku Teks
Denning, Melita
Llewellyn Publications, 1993
Buku Teks
Metz, Michael E., author
Brunner-Routledge, 2011
Buku Teks