www.rnib.org.uk/wesuppy/fctsheet/braille.htm
www.duxburyststems.com/braille.asp
www.his.com/~pshapiro/braille.html
www.rnib.org.us/wesupply/fctsheet/keller.htm
www.afb.org/info_document_view.asp?documentid=1350
www.factmonster.com/ipka/A0200808.html
www.infoplease.com/ipa/A0200808.html