Prevalence and underdiagnosis of chronic obstructive pulmonary disease among patients at risk in primary care - Hill, Kylie; Goldstein, R.; Guyatt, G.; Blouin, M.; Tan, W.; Davis, L.; Heels-Andsdell, D.; Erak, M.; Bragaglia, P.; Tamari, I.; Hodder, R.; Stanbrook, M. (Canadian Medical Association, 2010)