Jordi Gonzàlez Xavier Varona F. Xavier Roca Juan José Villanueva Analysis of Human Walking Based on aSpaces. 177-188 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3179&spage=177 2004 conf/amdo/2004 AMDO db/conf/amdo/amdo2004.html#GonzalezVRV04