Springer, A. E., Hoelscher, D. M., Kelder, S. H., Castrucci, B., & Perez, A. (2008). Prevalence of Physical Activity and Sedentary Behaviors by Metropolitan Status in 4th-, 8th-, and 11th-Grade Students in Texas, 2004-2005. Centers for Disease Control and Prevention.

Springer, Andrew E., Deanna M. Hoelscher, Steven H. Kelder, Brian Castrucci, and Adriana Perez. Prevalence of Physical Activity and Sedentary Behaviors By Metropolitan Status in 4th-, 8th-, and 11th-Grade Students in Texas, 2004-2005. Centers for Disease Control and Prevention, 2008.

Springer, Andrew E., et al. Prevalence of Physical Activity and Sedentary Behaviors By Metropolitan Status in 4th-, 8th-, and 11th-Grade Students in Texas, 2004-2005. Centers for Disease Control and Prevention, 2008.