@techreport{Martinez2011,
author = {Martinez, G. and Copen, C.E. and Abma, J.C.},
title= {Teenagers in the United States: Sexual activity, contraceptive use, and childbearing, 2006–2010 National Survey of Family Growth. Data from the National Survey of Family Growth},
year = {2011},
publisher = {National Center for Health Statistics},
address = {Washington},
institution = {Vital and Health Statistics 23(31)},
}