Reifer, Mary, author
Philosophical Library, 1955
Buku Referensi
Australian Agency for International Development, 1995
Buku Teks
LeMay, Harold, author
Facts on File, 1988
Buku Referensi
Tulloch, Sara
Oxford University Press, 1991
Buku Teks
edited by John Algeo
Cambridge University Press, 1993
Buku Referensi