R. L. Rauck, MD, “A randomized, open-label study of once-a-day AVINZA® (morphine sulfate extended-release capsules) versus twice-a-day OxyContin® (oxycodone hydrochloride controlled-release tablets) for chronic low back pain: The extension phase of the ACTION trial”, J of Opioid Management, vol. 2, no. 6, pp. 325–333, Nov. 2006.