Bien, Hans-Samuel; Stawitz, Josef; Wunderlich, Klaus (2000). "Anthraquinone Dyes and Intermediates". Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH, Weinheim. doi:10.1002/14356007.a02_355. ISBN3527306730.
gcrg.org
Behan, Jeff (Spring 1995). "The bug that changed history". Boatman's Quarterly Review. 8 (2). Grand Canyon River Guides. Archived from the original on 21 June 2006. Retrieved 5 January 2011.
Furry, Margaret S.; Viemont, Bess M. (August 1934). Home dyeing with natural dyes (Report). Washington, D.C.: U.S. Department of Agriculture, Bureau of Home Economics.
Behan, Jeff (Spring 1995). "The bug that changed history". Boatman's Quarterly Review. 8 (2). Grand Canyon River Guides. Archived from the original on 21 June 2006. Retrieved 5 January 2011.