Portenoy, MD, R. K., W. Raffaeli, MD, L. M. Torres, MD, T. Sitte, A. C. Deka, MD, I. G. Herrera, MD, and M. S. Wallace, MD. “Long-Term Safety, Tolerability, and Consistency of Effect of Fentanyl Pectin Nasal Spray for Breakthrough Cancer Pain in Opioid-Tolerant Patients”. Journal of Opioid Management, vol. 6, no. 5, Jan. 2018, pp. 319-28, doi:10.5055/jom.2010.0029.