Database resources of the National Center for Biotechnology Information: update. - Wheeler,D..L..; Church,D..M..; Edgar,R..; Federhen,S..; Helmberg,W..; Madden,T..L..; Pontius,J..U..; Schuler,G..D..; Schriml,L..M..; Sequeira,E..; Suzek,T..O..; Tatusova,T..A..; et al. (Nucleic Acids Research (Database issue), 2004)