1. Organic carbon content of Devonian black shale sequence sampled in drill cuttings from eighteen wells in western Pennsylvania;Claypool;U.S. Geol. Sur. Open-File Rep. No. 79-1665,1979
2. Organic carbon content of Devonian shale sequence sampled in drill cuttings from twenty wells in southwestern New York;Claypool,1980
3. The Appalachian basin—its depositional sequences and their geologic relationships;Colton,1970
4. Chattanooga Shale and related rocks of central Tennessee and nearby areas;Conant;U.S. Geol. Surv. Prof. Pap. No. 357,1961
5. Rock Color Chart;Goddard,1948