The National Center for Biotechnology Information's Protein Clusters Database. - William Klimke; Richa Agarwala; Azat Badretdin; Slava Chetvernin; Stacy Ciufo; Boris Fedorov; Boris Kiryutin; Kathleen O'Neill; Wolfgang Resch; Sergei Resenchuk; Susan Schafer; Igor Tolstoy; et al. (Nucleic Acids Res., 2009)

BioProject and BioSample databases at NCBI: facilitating capture and organization of metadata. - Tanya Barrett; Karen Clark; Robert Gevorgyan; Vyatcheslav Gorelenkov; Eugene Gribov; Ilene Karsch-Mizrachi; Michael Kimelman; Kim D. Pruitt; Sergei Resenchuk; Tatiana A. Tatusova; Eugene Yaschenko; James Ostell (Nucleic Acids Res., 2012)