Williams RE, Bosnic N, Sweeney CT, Duncan AW, Levine KB, Brogan M, Cook SF. Prevalence of opioid dispensings and concurrent gastrointestinal medications in Quebec. Pain Res Manag. 2008;13(5):395-400.
McKenna SP, Whalley D, Doward LC. Which outcomes are important in schizophrenia? Int J Methods Psychiatr Res. 2000;9(1):S58-67.