Schaefer, C.W. (March 1971). "Instar, Stadium, and Stage: A New Look at Old Questions". Bulletin of the Entomological Society of America. 17 (1): 17. doi:10.1093/besa/17.1.17c.
Dunker, Nicole; Wake, Marvalee H.; Olson, Wendy M. (January 2000). "Embryonic and Larval Development in the Caecilian Ichthyophis kohtaoensis (Amphibia, Gymnophiona): A Staging Table". Journal of Morphology. 243 (1): 3–34. doi:10.1002/(sici)1097-4687(200001)243:1<3::aid-jmor2>3.3.co;2-4. PMID10629095.
San Mauro, D.; Gower, D. J.; Oommen, O. V.; Wilkinson, M.; Zardoya, R. (November 2004). "Phylogeny of caecilian amphibians (Gymnophiona) based on complete mitochondrial genomes and nuclear RAG1". Molecular Phylogenetics and Evolution. 33 (2): 413–427. Bibcode:2004MolPE..33..413S. doi:10.1016/j.ympev.2004.05.014. PMID15336675.
San Mauro, D.; Gower, D. J.; Oommen, O. V.; Wilkinson, M.; Zardoya, R. (November 2004). "Phylogeny of caecilian amphibians (Gymnophiona) based on complete mitochondrial genomes and nuclear RAG1". Molecular Phylogenetics and Evolution. 33 (2): 413–427. Bibcode:2004MolPE..33..413S. doi:10.1016/j.ympev.2004.05.014. PMID15336675.
Dunker, Nicole; Wake, Marvalee H.; Olson, Wendy M. (January 2000). "Embryonic and Larval Development in the Caecilian Ichthyophis kohtaoensis (Amphibia, Gymnophiona): A Staging Table". Journal of Morphology. 243 (1): 3–34. doi:10.1002/(sici)1097-4687(200001)243:1<3::aid-jmor2>3.3.co;2-4. PMID10629095.
San Mauro, D.; Gower, D. J.; Oommen, O. V.; Wilkinson, M.; Zardoya, R. (November 2004). "Phylogeny of caecilian amphibians (Gymnophiona) based on complete mitochondrial genomes and nuclear RAG1". Molecular Phylogenetics and Evolution. 33 (2): 413–427. Bibcode:2004MolPE..33..413S. doi:10.1016/j.ympev.2004.05.014. PMID15336675.
Liddell, Henry George; Scott, Robert (1940). "Metamorphosis". A Greek-English Lexicon. Oxford: Clarendon Press. Retrieved 2012-08-26 – via perseus.tufts.edu.