TAKING BIOPSIES IN MACROSCOPICALLY NORMAL ENDOSCOPIES - IS THERE INTER-OPERATOR VARIABILITY AND NEED FOR STRINGENT GUIDELINES AND TRAINING? - Cianci, N; Varghese, B; Diossy, M; Agarwal, A; Radzi, A; Mandal, A; Khanna, A (Endoscopy, 2020)