The Genomes OnLine Database (GOLD) v.5: a metadata management system based on a four level (meta)genome project classification. - T. B. K. Reddy; Alex D. Thomas; Dimitri Stamatis; Jon Bertsch; Michelle Isbandi; Jakob Jansson; Jyothi Mallajosyula; Ioanna Pagani; Elizabeth A. Lobos; Nikos Kyrpides (Nucleic Acids Res., 2015)