Jennings, J. R., & Spurgeon, P. A. (1985). Pennsylvanian plants of Eastern Kentucky: A flora from the Breathitt formation near Grannies Branch and Rocky Branch of Goose Creek, Clay country, Kentucky. Kentucky Geological Survey.

Jennings, James R., and Paul A. Spurgeon. Pennsylvanian Plants of Eastern Kentucky: A Flora from the Breathitt Formation Near Grannies Branch and Rocky Branch of Goose Creek, Clay Country, Kentucky. Lexington: Kentucky Geological Survey, 1985.

Jennings, James R., and Paul A. Spurgeon. Pennsylvanian Plants of Eastern Kentucky: A Flora from the Breathitt Formation Near Grannies Branch and Rocky Branch of Goose Creek, Clay Country, Kentucky. Kentucky Geological Survey, 1985.