Geology Underfoot on Colorados Western SlopeJohn F. Shroder, Amy Ellwein, George Felix Engelmann, Carol Engelmann, Beth Waldron Yuhas · First published 2022Open the Tome
Roadside geology of NebraskaHarmon D. Maher, Harmon D., Jr. Maher, Robert D. Shuster, George Felix Engelmann · First published 2002Open the Tome
The logic of phylogenetic analysis and the phylogeny of the Xenarthra (Mammalia)George Felix Engelmann · First published 1978Open the Tome
