Niles Eldredge and Stephen Jay Gould, “Punctuated Equilibria: An Alternative to Phyletic Gradualism,” в Thomas Schopf, ed., Models in Paleobiology (San Francisco: Freeman, Cooper and Company, 1972), 82–115; Stephen Jay Gould and Niles Eldredge, “Punctuated Equilibria: The Tempo and Mode of Evolution Reconsidered,” Paleobiology 3, no. 2 (1977): 115–151.