A Prospective Randomized Comparative Study on the Safety and Tolerability of Transnasal Esophagogastroduodenoscopy - Yagi, J; Adachi, K; Arima, N; Tanaka, S; Ose, T; Azumi, T; Sasaki, H; Sato, M; Kinoshita, Y (Endoscopy, 2005)