On Discrete Gauge Symmetries in Trinification Model
  Given the important role of discrete gauge symmetries in viable models, we discuss these symmetries in intersecting D6-brane trinification model where the ZN symmetry is investigated and its identification is shown. 
R. Ahl Laamara, M. Drissi El Bouzaidi, S.-E. Ennadifi, S. Nassiri
hep-th