Essential Concepts in Clinical Research: Randomised Controlled Trials and Observational Epidemiology 2nd edition
Paperback by Schulz, Kenneth (Distinguished Scientist, FHI360, Durham, North Carolina, USA; Clinical Professor, Department of Obstetrics & Gynecology, University of North Carolina School of Medicine, Chapel Hill, NC, USA); Grimes, David A. (Clinical Professor, Department of Obstetrics and Gynecology, University of North Carolina School of Medicine, Chapel Hill, NC, USA)