Authors	Year	Title
Plummer & Hornberger	1935	Geology of Palo Pinto County, Texas. University of Texas Bulletin, 3534: 240 p., 28 fig., 7 pl.
Plummer & Scott	1937	Upper Paleozoic ammonites in Texas. The geology of Texas, vol.3 pt.1, Bull. Texas. Univ., 3701: 1-516, fig.1-88, pl.1-41; Austin, Texas.
Plummer	1950	The Carboniferous rocks of the Llano region of Central Texas. Publications of the University Texas, 4329: 1-170, pl.1-21; Austin.