1. Recent trends in cesarean delivery in the United States;Menacker;NCHS Data Brief,2010
2. Cesarean delivery on maternal request;National Institutes of Health State-of-the-Science Conference Statement;NIH Consensus and State-of-the-Science Statements,2006
3. Births: final data for 2006;Martin;National Vital Statistics Reports,2009
4. Healthy People 2020 http://www.healthypeople.gov/