Mechanical systems subjected to generalized nonholonomic constraints
  We study mechanical systems subject to constraint functions that can be dependent at some points and independent at the rest. Such systems are modelled by means of generalized codistributions. We discuss how the constraint force can transmit an impulse to the motion at the points of dependence and derive an explicit formula to obtain the ``post-impact'' momentum in terms of the ``pre-impact'' momentum. 
J. Cortes, M. de Leon, D. Martin de Diego, S. Martinez