http://www.the-arcturians.com/eng/
- Crop circle art/geometry

http://www.cropcircle-archive.com/1_UK/3_geo/geo.html
-The mathematical aspect in crop circles

http://www.michaelglickman.net
-Michael Glickman/Geometry and Sacred Geometry

http://www.temporarytemples.co.uk
-Crop circle image library/Steve Alexander

http://www.cropcircleconnector.com
-Crop circle site, archives, news