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.
Chicago-referens (17:e uppl.)Jennings, James R., och 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.
MLA-referens (9:e uppl.)Jennings, James R., och 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.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.