"A Basic Sedimentary Rock Classification", L.S. Fichter, Department of Geology/Environmental Science, James Madison University (JMU), Harrisonburg, Virginia, October 2000, JMU-sed-classifArquivado em 23 julho 2011 no Wayback Machine (accessed: March 2009): separates clastic, chemical & biochemical (organic).
"A Basic Sedimentary Rock Classification", L.S. Fichter, Department of Geology/Environmental Science, James Madison University (JMU), Harrisonburg, Virginia, October 2000, JMU-sed-classifArquivado em 23 julho 2011 no Wayback Machine (accessed: March 2009): separates clastic, chemical & biochemical (organic).