Thomlinson, Ralph, author
Random House , 1976
Buku Teks
Lynton, Rolf P.
Carolina Population Center, University of North Carolina , 1974
Buku Teks
Lane, Mary Turner
Carolina Population Center, 1974
Buku Teks
Puspa Swara, 1997
Buku Teks
UNESCO , 1977
Buku Teks