Issues in conducting epidemiologic research among elders: lessons from the MOBILIZE Boston Study.
Samelson EJ, Kelsey JL, Kiel DP, Roman AM, Cupples LA, Freeman MB, Jones RN, Hannan MT, Leveille SG, Gagnon MM, et al. Am J Epidemiol. 2008 Dec 15; 168(12):1444-51. Epub 2008 Oct 25.