Dumortier J, Napoleon B, Hedelius F et al. Unsedated transnasal EGD in daily practice: results with 1100 consecutive patients. Gastrointest. Endosc.2003; 57: 198-204.
Dumortier J, Ponchon T, Scoazec J et al. Prospective evaluation of transnasal esophagogastroduodenoscopy: feasibility and study on performance and tolerance. Gastrointest. Endosc.1999; 49: 285-91.
Zaman A, Hahn M, Hapke R, Knigge K, Fennerty M, Katon R. A randomized trial of peroral versus transnasal unsedated endoscopy using an ultrathin videoendoscope. Gastrointest. Endosc.1999; 49: 279-84.
Craig A, Hanlon J, Nursing D, Dent J, Shoeman M. A comparison of transnasal and transoral endoscopy with smalldiameter endoscopes in unsedated patients. Gastrointest. Endosc.1999; 49: 292-6.