Use of a Side‐Viewing Endoscope for Superficial Non‐Ampullary Duodenal Epithelial Tumors Located in the Groove Area - Kiyoyuki Kobayashi; Maki Ayaki; Takako Nomura; Hironobu Suto; Minoru Oshima; Keiichi Okano; Masafumi Ono; Hideki Kobara (JGH Open)