Michael A. Ruggiero, Dennis P. Gordon, Thomas M. Orrell, Nicolas Bailly, Thierry Bourgoin, Richard C. Brusca, Thomas Cavalier-Smith, Michael D. Guiry, Paul M. Kirk (2015): A Higher Level Classification of All Living Organisms. PLOS ONE 10(6): e0130114. doi:10.1371/journal.pone.0130114.
Andrew C. Jones, Richard J. White, Ewen R Orme (2011): Identifying and relating biological concepts in the Catalogue of Life. Journal of Biomedical Semantics 20112:7 doi:10.1186/2041-1480-2-7