^ 4.04.1Krupovič, Mart; Bamford, Dennis H. Virus evolution: how far does the double β-barrel viral lineage extend?. Nature Reviews Microbiology. December 2008, 6 (12): 941–948. PMID 19008892. doi:10.1038/nrmicro2033.
^Bamford, DH; Burnett, RM; Stuart, DI. Evolution of viral structure.. Theoretical Population Biology. 2002, 61 (4): 461–70. PMID 12167365. doi:10.1006/tpbi.2002.1591.