References
- Children's Defense Fund. 2008 . State of America's children Washington, DC : Author .
- Molnar , B. E. , Gortmaker , S. L. , Bull , F. C. and Buka , S. L. 2004 . Unsafe to play? Neighborhood disorder and lack of safety predict reduced physical activity among urban children and adolescents . American Journal of Health Promotion , 18 : 378 – 386 .