"PiHex Credits". Centre for Experimental and Constructive Mathematics. Simon Fraser University. March 21, 1999. Archived from the original on 2017-06-10. Retrieved 30 March 2018.
web.archive.org
"PiHex Credits". Centre for Experimental and Constructive Mathematics. Simon Fraser University. March 21, 1999. Archived from the original on 2017-06-10. Retrieved 30 March 2018.