RT Journal Article SR Electronic T1 The author responds to “Chronic obstructive pulmonary disease and Occam’s razor” JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E946 OP E946 DO 10.1503/cmaj.733142 VO 189 IS 28 A1 Andrea S. Gershon YR 2017 UL http://www.cmaj.ca/content/189/28/E946.abstract