1. Machining of holes: developments in drilling technology;Tönshoff;Annals of CIRP,1994
2. B.H. Chambers, Twist Drills, Edgar Allen, 1935.
3. S.A. Morse, Improvements in drill bits, American Patent No: 38, 1863.
4. Australian Standard, Twist drills (general purpose), 2438-1981, 1981.
5. International Standard, Twist drills—terms, definitions and types, ISO5419-1982, 1982.