Ludwig Retzbach released a new version of his 'Brushless Fibel" booklet. Everything you wanted to know about (diy) brushless motors but were afraid
to ask. It also deals with 'Halbach' magnet array motors. Unfortunalely, it's only available in the language of Wolfgang Amadeus von Goethe ;-)
More info and ordering:
http://www.dmfv.de/de/shop/buecher/d16.html 