RT Journal Article SR Electronic T1 Response to: “A comprehensive approach needed to address regional variation” JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E841 OP E841 DO 10.1503/cmaj.733086 VO 189 IS 24 A1 Jack V. Tu YR 2017 UL http://www.cmaj.ca/content/189/24/E841.abstract