BENTON, M.  1990.  The Reign of the Reptiles.  New York:  Crescent Books.

CARROLL, R. L.  1987.  Vertebrate Paleontology and Evolution.  New York:  W. H. Freeman.

DIXON, D.; Cox, B.; Savage, R. J. G.; Gardiner, B.  1993.  The Macmillan Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals.  A Visual Who's Who of Prehistoric Life.  New York:  Macmillan Publishing.

LEVIN, H. L.  1991.  The Earth Through Time, 4th ed.  New York:  Saunders College Publishing.

LEVI-SETTI, R.  1993.  Trilobites.  Chicago:  University of Chicago Press.

LIPPS, J. H., ed.  1993.  Fossil Prokaryotes and Protists.  Boston:  Blackwell Scientific.

MOORE, R. C., ed.  1956.  Treatise on Invertebrate Paleontology, Coelenterata.  Boulder:  Geological Society of America and University of Kansas.

MOORE, R. C., ed.  1960.  Treatise on Invertebrate Paleontology, Mollusca 1.  Boulder:  Geological Society of America and University of Kansas.

MOORE, R. C., ed.  1964.  Treatise on Invertebrate Paleontology, Mollusca 3.  Boulder:  Geological Society of America and University of Kansas.

MOORE, R. C., ed.  1969.  Treatise on Invertebrate Paleontology, Mollusca 6, Bivalvia.  Boulder:  Geological Society of America and University of Kansas.

MOORE, R. C.; Teichert, C., ed’s.  1971.  Treatise on Invertebrate Paleontology, Mollusca 6, Bivalvia (Oysters).  Boulder:  Geological Society of America.

MURRAY, J. W., ed.  1985.  Atlas of Invertebrate Macrofossils.  New York:  John Wiley & Sons.

ROGERS, J. W.  1993.  A History of the Earth.  New York:  Cambridge University Press.