See CW, Srinivasan M, Saravanan S, Oldenburg CE, Esterberg EJ, Ray KJ, Glaser TS, Tu EY, Zegans ME, McLeod SD, Acharya NR, Lietman TM. Prior elicitation and Bayesian analysis of the Steroids for Corneal Ulcers Trial. Ophthalmic Epidemiol. 2012 Dec;19(6):407-13.
Michels KB, Rothman KJ. Update on unethical use of placebos in randomised trials. Bioethics. 2003 Apr;17(2):188-204.