1. Standardized tests for determining the physical properties of mine rocks;Obert;U.S. Bureau of Mines Report of Investigations,1946
2. Richtlinien zur Durchführung von Druckversuchen an Gesteinen im Bergbau;International Bureau for Rock Mechanics,1964
3. Strength parameters of selected intermediate quality rocks—testing procedures;U.S. Corps of Engineers;Missouri River Division Laboratory Reports,1966
4. Strength parameters of selected intermediate quality rocks—testing procedures;U.S. Corps of Engineers;Missouri River Division Laboratory Reports,1966
5. ASTM. Standard method of test for unconfined compressive strength of rock core specimens. American Society for Testing and Materials. ASTM Designation D-2938-7a.