@inproceedings{HoellerAAAI20,
   title = {{HDDL:} An Extension to {PDDL} for Expressing Hierarchical Planning Problems},
   author = {Daniel H{\"{o}}ller and Gregor Behnke and Pascal Bercher and Susanne Biundo and Humbert Fiorino and
Damien Pellier and Ron Alford},
   booktitle = {Proceedings of the 34th {AAAI} Conference on Artificial Intelligence ({AAAI})},
   publisher = {{AAAI} Press},
   pages = {9883--9891},
   year = {2020}
}