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
Aranda E, Aparicio J, Alonso V, Garcia-Albeniz X, Garcia-Alfonso P, Salazar R, Valladares M, Vera R, Vieitez JM, Garcia-Carbonero R. SEOM clinical guidelines for diagnosis and treatment of metastatic colorectal cancer 2015. Clin Transl Oncol. 2015 Dec;17(12):972-81. doi: 10.1007/s12094-015-1434-4
Mangel AW, Wang J, Sherrill B, Gnanasakthy A, Ervin C, Fehnel SE. Urgency as an endpoint in irritable bowel syndrome. Gastroenterology Research. 2011 Feb 1;4(1):9-12.