1. A.S.T.M. D 2797. 1985 Preparing coal samples for microscopical analysis by reflected light
2. A.S.T.M. D2798. 1985 Microscopical determination of the reflectance of the organic components in a polished specimen of coal
3. Calculation of coking charges on the basis of petrographic characteristics of coals;Ammosov;Koks i khimiya,1957
4. Relationship between coal petrographic composition and coke stability;Benedict;Blast Furnace and Steel Plant,1968
5. B.S. 6127, Part 1. 1981 Glossary of terms relating to the petrographic analysis of bituminous coal and anthractite