Hiroaki Yano Masaki Nudejima Hiroo Iwata Development of Haptic Rendering Methods of Rigidity Distribution for Tool-Handling Type Haptic Interface. 569-570 2005 conf/haptics/2005 WHC http://csdl.computer.org/comp/proceedings/whc/2005/2310/00/23100569abs.htm db/conf/haptics/whc2005.html#YanoNI05