1. Appelbaum PS, Lidz CW, Klitzman R: Voluntariness of consent to research: a preliminary empirical investigation. IRB Ethics Human Res. 2009, 31: 10-14.
2. Black L, Batist G, Avard D, Rousseau C, Diaz Z, Knoppers BM: Physician recruitment of patients to non-therapeutic oncology clinical trials: ethics revisited. Front Pharmacol. 2013, 4: 25.
3. Levine RJ: Clinical trials and physicians as double agents. Yale J Biol Med. 1992, 65: 65-74.
4. Miller FG: Recruiting research participants. The Oxford Textbook of Clinical Research Ethics. Edited by: Emanuel EJ, Grady C, Crouch RA, Lie R, Miller F, Wendler D. 2008, Oxford, UK: Oxford University Press, 397-403.
5. Miller VA, Nelson RM: Factors related to voluntary parental decision-making in pediatric oncology. Pediatrics. 2012, 129: 903-909. 10.1542/peds.2011-3056.