The COG database: an updated version includes eukaryotes.
Roman L. TatusovNatalie D. FedorovaJohn D. JacksonAviva R. JacobsBoris KiryutinEugene V. KooninDmitri M. KrylovRaja MazumderSergei L. MekhedovAnastasia N. NikolskayaB. Sridhar RaoSergei SmirnovAlexander V. SverdlovSona VasudevanYuri I. WolfJodie J. YinDarren A. NatalePublished in: BMC Bioinform. (2003)