1. Boston, D. W. and Gilbert, W. W. (1936) The Torque and the Thrust of Small Urill Operations in Various Metals, Trans. ASME, 58
2. Galloway, D. F. and Morton, l. S. (1946) Practical Drilling Tests, Research Department, The Institute of Production Engineers, London
3. Wiriyacosol, S. and Armarego, E. J. A. (1979) Thrust and Torque Prediction in Drilling from a Cutting Mechanics Approach, Annals of the CIRP, 28, p.87
4. Kronenberg, M. (1963) Grundzuge der Zerspanungs lehre, V2, SpringerVerlag, Berlin
5. Lorenz, G. (1979) Helix Angle and Drill Performance, Annals of the CIRP, 28, p.83