Groenwold R, Uddin M, Roes K, de Boer A, Rivero-Ferrer E, Martin E, Gatto N, Klungel O. Instrumental variable analysis in randomized trials with non-compliance and observational pharmacoepidemiologic studies. OA Epidemiology. 2014 May 9;2(1):9.
Lovas K, Geher P, Whalley D, McKenna S, Meads D, Kalo Z. Hungarian adaptation of a disease-specific quality-of-life questionnaire in patients with ankylosing spondylitis. Orv Hetil. 2002 Aug 11;43(32):1893-7.