Forns J, Vegas O, Julvez J, Garcia-Esteban R, Rivera M, Lertxundi N, Guxens M, Fano E, Ferrer M, Grellier J, Ibarluzea J, Sunyer J. Association between child cortisol levels in saliva and neuropsychological development during the second year of life. Stress Health. 2014 Apr;30(2):142-8. doi: 10.1002/smi.2504
Michels KB, Rothman KJ. Update on unethical use of placebos in randomised trials. Bioethics. 2003 Apr;17(2):188-204.