Christensen T, Riis AH, Hatch EE, Wise LA, Nielsen MG, Rothman KJ, Toft Sorensen H, Mikkelsen EM. Costs and efficiency of online and offline recruitment methods: a web-based cohort study. J Med Internet Res. 2017 Mar 1;19(3):e58. doi: 10.2196/jmir.6716
Vallano A, Mendoza G, Rodríguez A, Rebordosa C. Seguridad de los analgesicos y de los antiinflamatorios. Farm Hosp. 2004;157:23-31.