R. Williams, PhD, MS, N. Bosnic, BA, A. W. Duncan, PhD, MS, M. Brogan, BA, and S. F. Cook, PhD, “Prevalence of opioid dispensings and concurrent gastrointestinal medications in an elderly population from Ontario, Canada”, J of Opioid Management, vol. 4, no. 4, pp. 193–200, Jan. 2018.