RT Journal Article SR Electronic T1 Clarifying the role of lung ultrasonography in COVID-19 respiratory disease JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E436 OP E436 DO 10.1503/cmaj.75311 VO 192 IS 16 A1 Cameron W. Pierce YR 2020 UL http://www.cmaj.ca/content/192/16/E436.abstract AB