compiled by Jonah Ohayv

I. The mathematical eqivalents of musical tones and crop-circle's geometrical relations, by Gerald Hawkins and others:

https://cropcircleconnector.com/ilyes/ilyes16.html
http://cropcircleconnector.com/Dutch/CROPCIRCLESAN%20QUANTUMMECHANICS.html
https://www.cropcirclesecrets.org/hawkins.html
https://www.cropcirclesecrets.org/crop_circles_theorems.html
https://www.cropcirclesecrets.org/hawkinsb.html
https://www.cropcirclesecrets.org/crop_circles_diatonics.html

II. The many-faceted crop-circle geometrical research of Bert Janssen:

https://www.cropcirclesandmore.com/content/welcome.html

III. Geometrical construction of crop-circles' shapes:

https://www.cropcircle-archive.com/1_UK/3_geo/geo.html click "geometry"
https://www.zefdamen.nl/CropCircles/en/Crop_circles_en.htm
https://www.sayer.abel.co.uk/geometry.htm
https://www.cropcirclesecrets.org/crop_circles_sacredgeo.html
https://www.martinkeitel.net/cropcircles/ under "articles & research"

IV. Pentagonal geometry behind crop-circles, by Wolfgang Schindler:

http://www.kornkreise.info/schindler (copy the address in a new window, open, click "T", then "evolution and geometry")

http://www.kornkreise.info/schindler/shape_and_geometry.pdf (copy the address in a new window and open it there)