HÖLDER, Helmut; PAPP, Adolf; VAN COUVERING, J. A.; KAUFFMAN, Erle G.; BERGGREN, W. A. Part A, Introduction, Ch. 5, p. 390-537. Treatise on Invertebrate Paleontology, [S. l.], 1979. DOI: 10.17161/dt.v0i0.5532. Disponível em: https://journals.ku.edu/InvertebratePaleo/article/view/5532. Acesso em: 2 apr. 2025.