An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
van Sluijs EM, van Poppel MN, Twisk JW, Chin A Paw MJ, Calfas KJ, van Mechelen W.van Sluijs EM, et al. Among authors: calfas kj.Am J Public Health. 2005 Oct;95(10):1825-31. doi: 10.2105/AJPH.2004.044537.Am J Public Health. 2005.PMID: 16186461Free PMC article.Clinical Trial.
Roesch SC, Norman GJ, Adams MA, Kerr J, Sallis JF, Ryan S, Calfas KJ, Patrick K.Roesch SC, et al. Among authors: calfas kj.J Health Psychol. 2009 Mar;14(2):313-25. doi: 10.1177/1359105308100216.J Health Psychol. 2009.PMID: 19237499Clinical Trial.