Gravitational Couplings for Generalized Orientifold Planes
  The Wess-Zumino action for generalized orientifold planes (GOp-planes) is presented and a series power expantion is realized from which processes that involves GOp-planes, RR-forms, gravitons and gaugeons, are obtained. Finally non-standard GOp-planes are showed. 
Juan Fernando Ospina Giraldo