@ARTICLE{Mavridis2015,
  author = {N. Mavridis and N. Bellotto and K. Iliopoulos and N. {Van de Weghe}},
  title = {{QTC3D: Extending the Qualitative Trajectory Calculus to Three Dimensions}},
  journal = {Information Sciences},
  year = {2015},
  volume = {322},
  pages = {20-30}
}