Schwartz, Peter, author
Doubleday, 1991
Buku Teks
Anand, Mulk Raj
Allen, 1933
Buku Teks
Morin, Relman
Alfred A. Knopf, 1960
Buku Teks
Long, Roberrt H.
Robert Morris Associates , 1990
Buku Teks
Epictetus
Al Burt, [date of publication not identified]
Buku Teks