Anderson, R. G., author
Macdonald & Evans, 1982
Buku Referensi
Campbell, Alastair, author
Chronicle Books, 2000
Buku Referensi
Houghton Miffiln, 1993
Buku Referensi
Wyatt, Allen L.
McGraw-Hill, 1990
Buku Referensi
Oxford University Press, 1990
Buku Referensi