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Huttenlocker, A. K.; Rega, E.; Sumida, S. S. (2010). "Comparative anatomy and osteohistology of hyperelongate neural spines in the sphenacodontids Sphenacodon and Dimetrodon (Amniota: Synapsida)". Journal of Morphology. 271 (12): 1407–1421. doi:10.1002/jmor.10876. PMID20886514. S2CID40899700.
Huttenlocker, A. K.; Rega, E.; Sumida, S. S. (2010). "Comparative anatomy and osteohistology of hyperelongate neural spines in the sphenacodontids Sphenacodon and Dimetrodon (Amniota: Synapsida)". Journal of Morphology. 271 (12): 1407–1421. doi:10.1002/jmor.10876. PMID20886514. S2CID40899700.