Rothschild, Bruce M., author
Springer, 2012
eBooks
United Nations Centre for Regional Development , 1983
Buku Teks
Klemstine, Charles F., author
Garland Publishing, 1984
Buku Teks
Beal, Edwin G., author
Library of Congress, 1950
Buku Teks
Teygeler, Rene, author
Hague, 2001
Buku Teks