Costello, Adam M. (30 Jan 1995), «Re: CRC», lista de correo png-list, http://pmt.sourceforge.net/mailing-lists/png-list/png-list.199501.gz, consultado el 29 de enero de 2010, «By the way, what would folks think of a Lee-style 7-paso scheme? Just the same thing, but starting with a 1/64 image? That would make the initial large pixels 8x8.»
