1. ASTM (1975a). Standard D-388. ASTM Standard Manual, Part 26, pp. 212-216.
2. ASTM (1975b). Standard D-2797. ASTM Standard Manual, Part 26, pp. 350-354.
3. Petrographic Investigation of Two Gondwana Seams from Madhya Pradesh, India
4. “Physical Methods in Determinative Mineralogy”;Bowie,1967