1. Hydraulic turbine contra-angle handpiece;Nelsen;JADA,1953
2. Dental handpiece history;Stephens;Aust Dent J,1987
3. Nelsen and the development of the high speed handpiece;Herschfeld;Bull Hist Dent,1987
4. The development of the dental high-speed air turbine handpiece, part 1;Dyson;Aust Dent J,1993
5. The era of high speed development in dentistry;Schulein;J Hist Dent,2002