The National Center for Biotechnology Information's Protein Clusters Database.
William KlimkeRicha AgarwalaAzat BadretdinSlava ChetverninStacy CiufoBoris FedorovBoris KiryutinKathleen O'NeillWolfgang ReschSergei ResenchukSusan SchaferIgor TolstoyTatiana A. TatusovaPublished in: Nucleic Acids Res. (2009)