Jaume Bacardit Michael Stout Jonathan D. Hirst Alfonso Valencia Robert Elliott Smith Natalio Krasnogor Automated Alphabet Reduction for Protein Datasets. 2009 10 BMC Bioinformatics http://dx.doi.org/10.1186/1471-2105-10-6 db/journals/bmcbi/bmcbi10.html#BacarditSHVSK09