Andrew A. Fisher, John E. Laing, John E. Stoeckel, John W. Townsend
Population Council, 1998
Buku Referensi
Stycos, J. Mayone
McGraw-Hill, 1971
Buku Teks
Stycos, J. Mayone
McGraw-Hill, 1971
Buku Teks
The University of Michigan Press, 1969
Buku Teks
University of Chicago, 1970
Buku Teks