Wala, PhD, E. P., Sloan, MD, P. A., & Holtman Jr, MD, PhD, J. R. (2011). Effect of prior treatment with ultra-low-dose morphine on opioid- and nerve injury-induced hyperalgesia in rats. Journal of Opioid Management, 7(5), 377–389. https://doi.org/10.5055/jom.2010.0079