Roger W. Brockett Ann Stokes Frank C. Park A Geometrical Formulation of the Dynamical Equations Describing Kinematic Chains. 637-641 1993 conf/icra/1993 ICRA (2) db/conf/icra/icra1993-2.html#BrockettSP93 http://dx.doi.org/10.1109/ROBOT.1993.291887