The Unesco Press, 1975
Buku Teks
Lynton, Rolf P.
Carolina Population Center, University of North Carolina , 1974
Buku Teks
Davis, Elisabeth B.
Marcel Dekker, 1981
Buku Referensi
Longmans, 1966/1967
Buku Teks
by W. D. Borrie [and others]
UNESCO, 1957
Buku Teks