RT Journal Article SR Electronic T1 Environmental and health impacts of ‘fracking’: why epidemiological studies are necessary JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 221 OP 222 DO 10.1136/jech-2015-205487 VO 70 IS 3 A1 Madelon L Finkel A1 Jake Hays YR 2016 UL http://jech.bmj.com/content/70/3/221.abstract AB