Karl Erich Wolff 'Particles' and 'Waves' as Understood by Temporal Concept Analysis. 126-141 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3127&spage=126 2004 conf/iccs/2004 ICCS db/conf/iccs/iccs2004.html#Wolff04