1. Geologic map of the Elkhorn City quadrangle, Kentucky-Virginia, and part of the Harman quadrangle, Pike County, Kentucky. U.S. Geological Survey Geologic Quadrangle Map, GQ-951, scale 1:24,000;Alvord,1971
2. The Carboniferous Period;Aretz,2020
3. The Mississippian and Pennsylvanian (Carboniferous) Systems in the United States- West Virginia and Maryland;Arkle;U.S. Geol. Surv. Prof. Pap.,1979
4. Nature and origin of early and late cherts in the Leadville limestone, Colorado;Banks;Geol. Soc. Am. Bull.,1970