^Pruyne, John; Jon T. Kilpinen (1996-11-02). "William Morris Davis". Valparaiso University Department of Geography and Meteorology. Diarsipkan dari versi asli tanggal 2010-08-28. Diakses tanggal 2010-08-18. Davis' contributions cover the separate fields of geography, geology, and meteorology.Parameter |url-status= yang tidak diketahui akan diabaikan (bantuan)
^Chorley, Richard J.; Beckinsale, Robert P.; Dunn, Antony J. (2005) [1973]. "Chapter Twenty-Two". The History of the Study of Landforms. Volume Two. Taylor & Francis e-Library. hlm. 569.
^Ford, Derek (2007). "Jovan Cvijić and the founding of karst geomorphology". Environmental Geology. 51 (5): 675–684. doi:10.1007/s00254-006-0379-x.Parameter |s2cid= yang tidak diketahui akan diabaikan (bantuan)