1. Basic studies of percussion drilling;Hartman;Min Eng,1959
2. Crater geometry relations in percussive drilling-single blos studies;Hartman;Mine Quarry Eng,1962
3. Mechanical properties and drillability of rocks;Protodyakonov,1962
4. Paone J, Madson D, Bruce WE. Drillability studies—laboratory percussive drilling. USBM RI 7300, 1969.
5. Tandanand S, Unger HF. Drillability determination—A drillability index of percussive drills. USBM RI 8073, 1975.