1. Mechanical properties and drillability of rocks;Protodyakonov,1962
2. Drillability and physical properties of rocks;Singh,1969
3. Principles of rock drilling;Clark;Colorado School Mines Quart,1979
4. An empirical equation for drill performance prediction;Rabia,1980
5. Drillability of rocks in percussive drilling from “energy per unit volume” as determined with a microbit;Pathinkar;J Min Eng,1980