Gracia Baena JM, Calaf Vall I, Zielonka M, Marsal Mora JR, Godoy P, Worner Diz F. Risk factors and comorbidities associated with severe aortic stenosis: a case-control study. Rev Clin Esp. 2021 May 23;221(5):249-57. doi: 10.1016/j.rce.2020.01.010.
Basarir H. Poor, multidimensionally speaking: evidence from South Africa. J Afr Econ. 2011 Jun 1;20(3):463-504. doi: 10.1093/jae/ejr001