Michels KB, Rothman KJ. Update on unethical use of placebos in randomised trials. Bioethics. 2003 Apr;17(2):188-204.
Palka P, Fleming AD, Lange A, Fenn LN, Sutherland GR, McDicken WN. Doppler myocardial imaging: mean myocardial velocity and velocity gradient in normal subjects. Poster presented at the British Cardiac Society Annual Meeting; May 23, 1995. Yorkshire, United Kingdom. [abstract] Brit Heart J. 1996 Nov 1; 73(5 suppl 3):85.