	Authors	Year	Title
	Boardman, Work & Mapes	1994	Biostratigraphy of Middle and Late Pennsylvanian (Desmoinesian-Virgilian) ammonoids. [Boardman,D.R., D.M.Work, Mapes,R.H. & Barrick,J.E.]. Kansas Geological Survey Bulletin 232, 121 p., 26 figs., 1 tabl., 5 pls., Lawrence, KS.
	Work & Mapes	2009	New occurrences of the Pennsylvanian index ammonoid Dunbarites from the North American Midcontinent Journal of Paleontology, vol. 83, pp. 405-413