@article{ref1,
title="Patterns of Vaginal, Oral, and Anal Sexual Intercourse in an Urban Seventh‐Grade Population",
journal="Journal of school health",
year="2009",
author="Markham, Christine M. and Fleschler Peskin, Melissa and Addy, Robert C. and Baumler, Elizabeth R. and Tortolero, Susan R.",
volume="79",
number="4",
pages="193-200",
abstract="Background:  This study examines the prevalence of vaginal, oral, and anal intercourse among a population of urban, public middle school students, the characteristics of early sexual initiators, and the sequence of sexual initiation. Such data are limited for early adolescents.<p />",
language="",
issn="0022-4391",
doi="10.1111/j.1746-1561.2008.00389.x",
url="http://dx.doi.org/10.1111/j.1746-1561.2008.00389.x"
}