Lewis, C. S.
Harpercollins, 1999
Buku Teks
Ryan, Cornelius, author
Simon and Schuster, 1966
Buku Teks
Pausch, Randy, author
Hodder & Stoughton, 2008
Buku Teks
Hough, Graham, author
Barnes & Noble, 1961
Buku Teks
edited by Mark Collins ; foreword by David Attenborough
Oxford University Press, 1990
Buku Teks