Reference:
Matthes, K., Sankaranarayanan, G., Ahn, W., and De, S. (2012). Simulator-based training of NOTES procedures.
In A. N. Kalloo, J. Marescaux, and R. Zorron (Eds.), Natural Orifice Translumenal Endoscopic Surgery: Textbook and Video Atlas. John Wiley & Sons.