Mohamed Tajine Alain Daurat On Local Definitions of Length of Digital Curves. 114-123 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2886&spage=114 2003 conf/dgci/2003 DGCI db/conf/dgci/dgci2003.html#TajineD03