edited by Thomas A. Sebeok
Mouton, 1971
Buku Referensi
Esacove, Anne, author
Oxford University Press, 2016
eBooks
Mertz, Robert Anton
Westerview Press, 22 cm
Buku Teks
UK Department for International Development and the Natural Environment Research Council, 2015
Majalah, Jurnal, Buletin
Ridker, Ronald G.
Washinton The World Bank 1994,
Buku Teks