Dixon, Ruth B., author
Published for Resources for the Future by the Johns Hopkins Press, 1978
Buku Teks
editor, Gabriele Koehler, Deepta Chopra
Routledge, 2014
Buku Teks
D. Reidel Publishing Company, 1985
Buku Teks
Whyte, Robert Orr, author
Westview Press, 1982
Buku Teks
Nelson, Nici
Pergamon Press, 1979
Buku Teks