Additional professional research into the crop circle phenomenon is relatively sparse -- partially, we suspect, because the mass media attributes crop circles to "pranks with planks" (manual flattening of the crops by people) which has resulted in there being little funding available to support serious scientific inquiry. We list below a few links to other work which has been carried out which may be of interest.
H-GLAZE REPORT: Rodney Ashby's additional and highly interesting findings regarding the magnetic glaze found at Cherhill, UK in 1993.
SHORT-LIVED RADIONUCLIDES: Study carried out in 1991 in England by Marshall Dudley and Michael Chorost, which reported the discovery of 13 short-lived radio- nuclides in soil samples from a British crop circle.
COMMENTS on Levengood, W.C. and Talbott, N.P. (1999), "Dispersion of Energies in Worldwide Crop Formations," Physiol. Plant.105:615-624. Remarks by James W. Deardorff, Ph.D., Professor Emeritus, College of Oceanic & Atmospheric Sciences, Oregon State University.
http://www.blackwell-synergy.com (must be a subscriber to Physiologia Plantarum)
or email Dr. Deardorff at email@example.com
COMMENTS on Levengood, W.C. and Talbott, N.P. (1999) "Dispersion of Energies in Worldwide Crop Formations," Physiol. Plant.105:615-624. Remarks by Eltjo H. Haselhoff, Ph.D, in Letters to the Editors.
http://www.ecn.org/cufi/Haselhoff.pdf or email Dr. Haselhoff at firstname.lastname@example.org
METEOROLOGICAL INTERPRETATION: British meteorologist George Terence Meaden spent considerable time investigating crop circles in the 1980s and came to the conclusion that "simple" circles were caused by local wind vortices and that all others were man-made. He authored several books which are now, unfortunately, out of print, but he has posted a summary of his opinion on the web and can be contacted for further comment.
TRILLING NOISE EVALUATION: Fourier analysis, by Paul Vigay, comparing song of British songbird (the Grass- hopper Warbler) to "trilling noise" captured on tape at a crop circle site in 1989. (See "Early work & theories") http://www.cropcircleresearch.com/research/harmonics1.html
GEOMETRY & CROP CIRCLES: Many individuals interested in crop circles have been intrigued by the complex geometry inherent in a number of formations. How such precision is accomplished on undulating and/or sloping fields, covering large areas of ground, in the dark of night and in all types of weather, stimulates real curiosity. The fact that many of the standing-crop elements found inside crop circle perimeters could have only been referenced from external points in the cropfield -- where the crop is found to be untouched -- adds to the mystery. There are many web-sties which investigate this aspect of the circles; here are a few:
Hawkins also discovered a fifth, more general, Euclidean theorem, from which he could derive the other four. However he could find no reference to this fifth theorem in the works of Euclid or elsewhere, and he subsequently challenged the readers of both Science News and The Mathematics Teacher to come up with this unpublished theorem. See the article published in Science News (Oct. 12, 1996) at:
Zef Damen, PhD., a Dutch electrical engineer in the tele-communications industry provides step-by-step constructions of a number of crop circles, showing the basic geometries involved.
Bert Jansen, also from The Netherlands, is a producer, photographer and award-winning videographer in the crop circle field who is also writing a booklet on the geometry found in crop circles. (Click on "Crop Circles" on left-hand side, then scroll down to "Crop Circle Reconstructions" & "Crop Circle Geometry.")
http://www.bertjanssen.nl (scan down to "Crop Circle Geometry")
Judy Arndt, an Alberta, Canada crop circle fieldworker and photographer, has also included analyses of geometries found in some of the Canadian circles she presents.