Nezhat, Camran (2011). "Chapter 23: 1980's". Nezhat's History of Endoscopy: A Historical Analysis of Endoscopy's Ascension Since Antiquity. Tuttlingen, Germany: Endo-Press. Archived from the original on 2018-07-27. Retrieved 2017-10-04.
Nezhat, Camran (2011). "Chapter 23: 1980's". Nezhat's History of Endoscopy: A Historical Analysis of Endoscopy's Ascension Since Antiquity. Tuttlingen, Germany: Endo-Press. Archived from the original on 2018-07-27. Retrieved 2017-10-04.