Zhu Weimo, Mahar Matthew T, Welk Gregory J, Going Scott B, Cureton Kirk J
Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Am J Prev Med. 2011 Oct;41(4 Suppl 2):S68-76. doi: 10.1016/j.amepre.2011.07.001.