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
Scotland GS, Philip S, Fleming AD, Goatman KA, Sharp PF, McNamee P, Fonseca S, Prescott G, Olson JA. Manual versus automated: the diabetic retinopathy screening debate. OTE. 2008 Jan 1;4(2):14-6.
Campo R, Brullet E, Montserrat A, Calvet X, Rivero E, Brotons C. Topical pharyngeal anesthesia improves tolerance of upper gastrointestinal endoscopy: a randomized double-blind study. Endoscopy. 1995 Nov;27(9):659-64.