1. S. A. MORSE, “Improvement in Drill Bits”, U.S. Patent Office (1863)
2. D. F. GALLOWAY and I. MORTON, “Practical Drilling Tests” Res. Dept. Inst. Prod. Engrs. (1946)
3. The Machining of Metals;ARMAREGO,1969
4. Tool Design;DONALDSON,1973
5. Tool Engineers' Handbook;A.S.T.M.E.,1958