N. Hawkins, R. Sanson-Fisher, A. Shakeshaft, C. D'Este, and L. Green. American journal of preventive medicine, 33 (2):
162-8(August 2007)4640<m:linebreak></m:linebreak>LR: 20071115; JID: 8704773; RF: 73; 2006/05/16 received; 2007/02/23 revised; 2007/03/31 accepted; ppublish;<m:linebreak></m:linebreak>Tipus d'estudis.