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Dalla Valle, L.; Nardi, A.; Belvedere, P.; Toni, M.; Alibardi, L. (2007). «Beta-keratins of differentiating epidermis of snake comprise glycine-proline-serine-rich proteins with an avian-like gene organization». Developmental Dynamics236 (7): 1939-1953. PMID17576619. doi:10.1002/dvdy.21202.
Dalla Valle, L.; Nardi, A.; Toffolo, V.; Niero, C.; Toni, M.; Alibardi, L. (2007). «Cloning and characterization of scale beta-keratins in the differentiating epidermis of geckoes show they are glycine-proline-serine-rich proteins with a central motif homologous to avian beta-keratins». Developmental Dynamics236 (2): 374-388. PMID17191254. doi:10.1002/dvdy.21022.
Nudds, R. L.; Dyke, G. J. (2010). «Narrow Primary Feather Rachises in Confuciusornis and Archaeopteryx Suggest Poor Flight Ability». Science328: 887-889. PMID20466930. doi:10.1126/science.1188895.
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