Oded Maler Dejan Nickovic Monitoring Temporal Properties of Continuous Signals. 152-166 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3253&spage=152 2004 conf/formats/2004 FORMATS/FTRTFT db/conf/formats/formats2004.html#MalerN04