RT Journal Article SR Electronic T1 Intraoperative upper gastrointestinal endoscopy and biopsy JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 67 OP 70 VO 41 IS 2 A1 Sivak, Michael V. A1 Esselstyn, Caldwell B. A1 Owens, Francis J. YR 1974 UL http://www.ccjm.org/content/41/2/67.abstract AB