Path planning in the presence of vertical obstacles

@article{Gewali1990PathPI,
  title={Path planning in the presence of vertical obstacles},
  author={Laxmi P. Gewali and Simeon C. Ntafos and Ioannis G. Tollis},
  journal={IEEE Trans. Robotics and Automation},
  year={1990},
  volume={6},
  pages={331-341}
}