http://www.augsburg.edu/math/faculty/doree/bulgarian_solitaire_bib.pdf that contains more than a dozen references that were inspired by the Gardner article.  Further information can be found in the Wikipedia article http://en.wikipedia.org/wiki/Bulgarian_ solitaire .  We received correct solutions from:   Philippe Fondanaiche (France) Sébastien Dumortier (France) Patrick LoPresti (USA) Fondanaiche sent us his own solution that is based on