On Action Functionals for Interacting Brane Systems
  We present an action functional and derive equations of motion for a coupled system of a bosonic Dp--brane and an open string ending on the Dp-brane. With this example we address the key issues of the recently proposed method (hep-th/9905144, hep-th/9906041) for the construction of manifestly supersymmetric action functionals for interacting superbrane systems. We clarify, in particular, how the arbitrariness in sources localized on the intersection is related to the standard description of the flat D-branes as rigid planes where the string for endpoints 'live'. 
Igor Bandos and Wolfgang Kummer