Whipple, Leon
Da Capo Press, 1972
Buku Teks
Lee, Je-won, author
Dusandonga, 2007
Buku Teks
Pritchard, Jim, author
American Management Association, 2006
eBooks
Wee, Chow Hou, author
Addison-Wesley, 2000
Buku Teks
Krishna, Anand, author
Centre for Vedic and Dharmic Studies, 2015
Buku Teks