Gastroenterology: Histopathological investigation of distal esophageal spasm (DES) using per‐oral endoscopic myotomy (POEM). Issue 7 (July 2015) - Takahashi, K; Sato, H; Sato, Y; Takeuchi, M; Takeda, S‐R; Mizuno, K; Hashimoto, S; Hasegawa, G; Kobayashi, M