Hejnol, A. (4 August 2010). "A Twist in Time—The Evolution of Spiral Cleavage in the Light of Animal Phylogeny". Integrative and Comparative Biology. 50 (5): 695–706. doi:10.1093/icb/icq103. PMID21558233.
Hejnol, A. (4 August 2010). "A Twist in Time—The Evolution of Spiral Cleavage in the Light of Animal Phylogeny". Integrative and Comparative Biology. 50 (5): 695–706. doi:10.1093/icb/icq103. PMID21558233.