E. M. Manning and B. J. MacFadden. 1989. Pliocene three-toed horses from Louisiana, with comments on the Citronelle Formation. Tulane Studies in Geology and Paleontology 22(2):35-46
W. C. Isphording and G. M. Lamb. 1971. Age and origin of the Citronelle Formation in Alabama. Geological Society America Bulletin 82:775-780