Não informado. (1968). Vital and health statistics. National Center for Health Statistics.
Chicago-Zitierstil (17. Ausg.)Não informado. Vital and Health Statistics. Washington: National Center for Health Statistics, 1968.
MLA-Zitierstil (8. Ausg.)Não informado. Vital and Health Statistics. National Center for Health Statistics, 1968.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.