Piggin, Stuart
The University of Wollongong, 1984
Buku Teks
edited by, John T. McNeill; translated and indexed by, Ford Lewis Battles
The Westminster Press, [date of publication not identified]
Buku Teks
Long, Edward LeRoy
Oxford University Press , 1967
Buku Teks
Beheim-Schwarzbach, Martin
Hamburg Rowohlt 1964
Buku Teks
by Jack Canfield ... [and others]
Health Communication, 1997
Buku Teks