Hedges, SB; Marin, J; Suleski, M; Paymer, M; Kumar, S (2015). "Tree of Life Reveals Clock-Like Speciation and Diversification". Mol Biol Evol. 32 (4): 835–845. arXiv:1412.4312. doi:10.1093/molbev/msv037. PMC 4379413. PMID 25739733. http://www.timetree.org/