1. Janvier, P. Early Vertebrates (Oxford Univ. Press, Oxford, (1996 )).
2. Rosen, D. E., Forey, P. L., Gardiner, B. G. & Patterson, C. Lungfishes, tetrapods, paleontology and plesiomorphy. Bull. Am. Mus. Nat. Hist. 167, 159–276 (1981).
3. Yu, X. Anew porolepiform-like fish, Psarolepis romeri, gen. et. sp. nov. (Sarcopterygii, Osteichthyes) from the Lower Devonian of Yunnan, China. J. Vert. Paleontol. 18, 261–274 ( 1998).
4. Zhu, M. & Schultz, H. -P. The oldest sarcopterygian fish. Lethaia 30, 293–304 (1997).
5. Tong-Duzy, T., Ta-Hoa, P., Boucot, A. J., Goujet, D. & Janvier, P. Vertébrés siluriens du Viet-nam central. C.R. Acad. Sci. Abstr. 32, 1023–1030 (1997).