edited by John Canning
Taplinger, 1967
Buku Referensi
Spronsen, J.W. van, author
Elsevier, 1969
Buku Teks
See, Lisa, author
Vintage Books, 2012
Buku Teks
Williams, Melanie, author
Cavendish Publishing Limited, 2002
Buku Teks
Ministry of Foreign Affairs, 1975
Buku Teks