Raghunathan K, Layton JB, Ohnuma T, Shaw AD. Observational research using propensity scores. Adv Chronic Kidney Dis. 2016 Nov;23(6):367-72. doi: 10.1053/j.ackd.2016.11.010
The National Institute of Child Health and Human Development Early Child Care Research Network, McLeod LD. Psychosocial and lifestyle factors associated with early-onset persistent and late-onset asthma. J Child Health Care. 2010;39(3):185-98.