Viren Swami
BPS Blackwell, 2011
Buku Teks
Nettle, Daniel
Oxford Univesity Press, 2009
Buku Teks
Walter, Alex
Springer, 2012
eBooks
William Damon, editor-in-chief
John Wiley & Sons, 1998
Buku Referensi
Ouspensky, P.D.
Hodder and Stoughton, 1957
Buku Teks