Jordi Artigas Carsten Preusche Gerd Hirzinger Time domain passivity for delayed haptic telepresence with energy reference. 1612-1617 2007 IROS http://dx.doi.org/10.1109/IROS.2007.4399570 conf/iros/2007 db/conf/iros/iros2007.html#ArtigasPH07