Assessment of Tumor Invasion of the Distal Esophagus in Carcinoma of the Cardia Using Endoscopic Ultrasonography - Natsugoe, S; Yoshinaka, H; Moringa, T; Shimada, M; Hokita, S; Baba, M; Takao, S; Fukumoto, T; Stein, H J; Aikou, T (Endoscopy, 1996)