RT Journal Article SR Electronic T1 COVID-19 has no effect on gravity JF BMJ Surgery, Interventions, & Health Technologies FD BMJ Publishing Group Ltd SP e000046 DO 10.1136/bmjsit-2020-000046 VO 2 IS 1 A1 Peter McCulloch A1 Art Sedrakyan YR 2020 UL http://sit.bmj.com/content/2/1/e000046.abstract