Resser, C.E.; Howell, B.F. (1938), "Lower Cambrian Olenellus zone of the Appalachians", Bulletin of the Geological Society of America, 49 (2): 195–248, Bibcode:1938GSAB...49..195R, doi:10.1130/GSAB-49-195
Taylor, J.F.; Durika, N.J. (1990), Lithofacies, trilobite faunas, and correlation of the Kinzers, Ledger, and Conestoga Formations in the Conestoga Valley [Chapter IX] In: Carbonates, schists, and geomorphology in the vicinity of the lower reaches of the Susquehanna River; 55th annual field conference of Pennsylvania geologists: Field Conference of Pennsylvania Geologists, no. 55, p. 136-160.
Resser, C.E.; Howell, B.F. (1938), "Lower Cambrian Olenellus zone of the Appalachians", Bulletin of the Geological Society of America, 49 (2): 195–248, Bibcode:1938GSAB...49..195R, doi:10.1130/GSAB-49-195