1. API recommended practice for core-analysis procedure;American Petroleum Institute;Am. Petrol. Inst. Recommended Practice RP 40,1960
2. Methods for sampling and testing mineral aggregates, sands and fillers;British Standards Institution;British Standard 812,1967
3. Methods of testing soils for civil engineering purposes;British Standards Institution;British Standard 1377,1967
4. Porosity and permeability analysis;Buell,1949
5. Rock mechanics and earthworks engineering part 5; quantitative classification of rock materials;Duncan;Muck Shifter,1966