Groenendael, Victoria M. Clara van
Foris Publications, 1987
Buku Referensi
Salmon, Claudine
Editions de la Maison des sciences de l'homme, 1981
Buku Referensi
United Nations Centre for Regional Development , 1983
Buku Teks
Greenwood Press, 1977
Buku Referensi
Freedman, Ronald
Irvington, 1975
Buku Teks