%0 Generic %A Elwood, J. Mark. %@ 9780191723865 (ebook) : %@ 019172386X (ebook) : %T Critical appraisal of epidemiological studies and clinical trials %U https://ezaccess.libraries.psu.edu/login?url=http://dx.doi.org/10.1093/acprof:oso/9780198529552.001.0001 %7 3rd ed.