Methodological framework for development of competence standards for optical diagnosis in gastrointestinal endoscopy: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement - Houwen, Britt B. S. L.; Hassan, Cesare; Hazewinkel, Yark; Vleugels, Jasper L. A.; Dinis-Ribeiro, Mario; Greuter, Marjolein J. E.; Coupé, Veerle M. H.; Dekker, Evelien; Bisschops, Raf (Endoscopy, 2021)