By Seth Stein (Dept. of Geological Sciences, Northwestern University, Evanston, IL), Michael Wysession (Dept. of Earth and Planetary Sciences, Washington University, St. Louis, MO)
By Stephen A. Greene (Associate Professor of Veterinary Anesthesia, Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL)
By Mary Jane Sterling (Bradley University, Peoria, IL)