Neil D. Jones Nina Bohr Termination Analysis of the Untyped lamba-Calculus. 1-23 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3091&spage=1 2004 conf/rta/2004 RTA db/conf/rta/rta2004.html#JonesB04