Rich, T. H.; Hopson, J. A.; Musser, A. M.; Flannery, T. F.; Vickers-Rich, P. (2005). Independent origins of middle ear bones in monotremes and therians. Science. 307 (5711): 910—914. doi:10.1126/science.1105717. PMID15705848.
nih.gov
pubmed.ncbi.nlm.nih.gov
Rich, T. H.; Hopson, J. A.; Musser, A. M.; Flannery, T. F.; Vickers-Rich, P. (2005). Independent origins of middle ear bones in monotremes and therians. Science. 307 (5711): 910—914. doi:10.1126/science.1105717. PMID15705848.