Hong J, Novick D, Montgomery W, Aguado J, Dueñas H, Peng X, Haro JM. Should unexplained painful physical symptoms be considered within the spectrum of depressive symptoms? Clin Pract Epidemiol Ment Health. 2015 Mar 31;11:130-9. doi: 10.2174/1745017901511010130
Michels KB, Rothman KJ. Update on unethical use of placebos in randomised trials. Bioethics. 2003 Apr;17(2):188-204.