Vierdag, E.W.
Martinus Nijhoff, 1973
Buku Teks
McBeth, Adam, author
Oxford Univ Press, 2011
Buku Teks
UNESCO, 1977
Buku Teks
edited by Jeffrey F. Addicott, Md. Jahid Hossain Bhuiyan, Tareq M.R. Chowdhur
Oxford University press, 2012
Buku Teks
Vega, Connie de la, author
Edward Elgar, 2013
Buku Referensi