1. Selection of optical illusions at /J002330/opill.htm from Optical illusions by Gaurav Sharma http://msnhomepages.talkcity.com/StageSt/gaurav_sharma, Gaurav Sharma, gaurav07@emirates.net.aem, March 2000.  Email message.

2. Selection of optical illusions at /J002330/opill.htm from Optical Illusion(s) http://hometown.aol.com/iilllusion/index.html, Iilllusion@aol.com, March 2000.  Email message.

3.  All stereograms at /J002330/stereograms.htm from Galen's Castle http://www.net1plus.com/users/darias, George Emond, darias@net1plus.com, March 2000.  Email message.

4.  Note: Photograph used at /J002330/visionsim.htm taken from public library of photos on Print Artist 4.0, by Sierra On-Line Inc.

5.  Note: Message Board used at  /J002330/cgi-bin/UltraBoard/UltraBoard.cgi downloaded from public supplier Homepagetools http://www.homepagetools.com/ultraboard/.  We have registered with the website, as required.  March 2000.