Zgierska, MD, PhD, A., Brown, MD, R. T., Zuelsdorff, BS, M., Brown, PhD, D., Zhang, PhD, Z. and Fleming, MD, MPH, M. F. (2007) “Sleep and daytime sleepiness problems among patients with chronic noncancerous pain receiving long-term opioid therapy: A cross-sectional study”, Journal of Opioid Management, 3(6), pp. 317–327. doi: 10.5055/jom.2007.0020.