Michels KB, Rothman KJ. Update on unethical use of placebos in randomised trials. Bioethics. 2003 Apr;17(2):188-204.
Küçükdeveci AA, McKenna SP, Kutlay S, Gürsel Y, Whalley D, Arasýl T. The development and psychometric assessment of the Turkish version of the Nottingham Health Profile. Int J Rehabil Res. 2000 Mar 1;23(1):31-8.