Riggs, Fred W.
Rajawali, 1985, 1988
Buku Teks
Riggs, Fred W.
Houghton Miffiln, 1964
Buku Teks
Rianto Nugroho
Pustaka Pelajar, 2012
Buku Teks
Samodra Wibawa, translator
Liberty, 1992
Buku Teks
Ross, Harold
United Nations Research Institute for Social Development, 1972
Buku Teks