Jacobsen, MS, MPH, R., C. Møldrup, PhD, and L. Christrup, PhD. “Clinical Rationale for Administering Fentanyl to Cancer Pain Patients: Two Delphi Surveys of Pain Management Experts in Denmark”. Journal of Opioid Management, vol. 4, no. 6, Jan. 2018, pp. 383-91, doi:10.5055/jom.2008.0042.