Radim Belohlávek Vladimir Sklenar Jiri Zacpal Erik Sigmund Evaluation of Questionnaires Supported by Formal Concept Analysis. 2007 CLA http://ceur-ws.org/Vol-331/Belohlavek2.pdf conf/cla/2007 db/conf/cla/cla2007.html#BelohlavekSZS07