Han, MD, PhD, H., Kass, DVM, PhD, P. H., Wilsey, MD, B. L. and Li, PhD, C.-S. (2013) “Age, gender, and earlier opioid requirement associations with the rate of dose escalation in long-term opioid therapy”, Journal of Opioid Management, 9(2), p. 129—138. doi: 10.5055/jom.2012.0154.