Brown RT, L Diaz-Ramirez G, W Boscardin J, Lee SJ, Steinman MA. Functional Impairment and Decline in Middle Age: A Cohort Study. Annals of Internal Medicine. 2017;167(11):761-768. doi:10.7326/M17-0496.

Lee SJ, Sudore RL, Williams BA, Lindquist K, Chen HL, Covinsky KE. Functional limitations, socioeconomic status, and all-cause mortality in moderate alcohol drinkers. J Am Geriatr Soc. 2009;57(6):955-62. doi:10.1111/j.1532-5415.2009.02184.x.