Christoph Grimm Wilhelm Heupke Klaus Waldschmidt Semi-Symbolic Modeling and Analysis of Noise in Heterogeneous Systems . 56-68 2004 FDL http://www.ecsi-association.org/ecsi/main.asp?l1=library&fn=def&id=545 conf/fdl/2004 db/conf/fdl/fdl2004.html#GrimmHW04