1. A comparison of observational studies and randomized, controlled trials;Benson;New England Journal of Medicine,2000
2. Comparative effectiveness research: what is it and why do we need it in nephrology?;Chang;Nephrology Dialysis Transplantation: Official Publication of the European Dialysis and Transplant Association – European Renal Association,2012
3. Randomized, controlled trials, observational studies, and the hierarchy of research designs;Concato;New England Journal of Medicine,2000
4. Directive 2001/20/EC of the European Parliament and of the Council of 4 April 2001 on the Approximation of the Laws, Regulations and Administrative Provisions of the Member States Relating to the Implementation of Good Clinical Practice in the Conduct of Clinical Trials on Medicinal Products for Human Use, 2001.
5. Reforming the regulations governing research with human subjects;Emanuel;New England Journal of Medicine,2011