Hill, R. T., Dall, W. H., Bagg, R. M., Vaughan, T., Wolff, J., Turner, H., . . . Agassiz, A. (1898). The Geological History of the Isthmus of Panama and Portions of Costa Rica.: Based upon a Reconnoissance made for Alexander Agassiz. Cambridge, Mass., U.S.A.: Printed for the Museum.

Hill, Robert T., William H. Dall, R. M. Bagg, T.W Vaughan, J.E Wolff, H.W Turner, Ahe Sjôgren, and Alexander Agassiz. The Geological History of the Isthmus of Panama and Portions of Costa Rica.: Based Upon a Reconnoissance Made for Alexander Agassiz. Cambridge, Mass., U.S.A.: Printed for the Museum, 1898.

Hill, Robert T., et al. The Geological History of the Isthmus of Panama and Portions of Costa Rica.: Based Upon a Reconnoissance Made for Alexander Agassiz. Cambridge, Mass., U.S.A.: Printed for the Museum, 1898.