The following is a representative sample of publications.
Julius, B.R., Ward, B.A., Stein, J.H., McBride, P.E., Fiore, M.C., Baker, T.B., Nieto, F.J., & Colbert, L.H. (2011). Ambulatory activity and associations with cardiovascular and metabolic risk factors in smokers. Journal of Physical Activity and Health, 8, 994-1003.