Closure of the Isthmus of Panama: The Near-Shore Marine Record of Costa Rica and Western Panamav. 104814–828
Coates, Anthony G., Jackson, Jeremy B. C., and Collins, Laurel S. 1992. "Closure of the Isthmus of Panama: The Near-Shore Marine Record of Costa Rica and Western Panama." Geological Society of America Bulletin, 104 814–828.