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-viite (17. p.)Jennings, James R., ja 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-viite (9. p.)Jennings, James R., ja 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.
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