1982,
Buku Teks SO
edited by James F. Phillips, John A. Ross
Clarendon Press, 1992
Buku Teks
Nortman, Dorothy L.
Population Council, 1978
Buku Teks SO
The University of Mincigan, 1969
Buku Teks SO
Stycos, J. Mayone
Appleton Century Crofts, 1973
Buku Teks SO