Julia Limberg Rudolf Seising Fuzzy Set Theory and Philosophical Foundations of Medicine. 409-416 2007 EUSFLAT Conf. (1) http://www.eusflat.org/publications/proceedings/EUSFLAT_2007/papers/Limberg_Julia_(148).pdf conf/eusflat/2007-1 db/conf/eusflat/eusflat2007-1.html#LimbergS07