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.
Julvez J, Forns M, Ribas-Fito N, Mazon C, Torrent M, Garcia-Esteban R, Ellison-Loschmann L, Sunyer J. Psychometric characteristics of the California Preschool Social Competence Scale in a spanish population sample. Early Educ Dev. 2008;19(5):795-815.
Phanikumar CV, Maitra B. Willingness-to-pay and preference heterogeneity for rural bus attributes. J Transp Eng A-Syst. 2007 Jan;133(1).