@inproceedings{GaspersKoivistoLiedloffOrdyniakSzeider12,
 author = {Serge Gaspers and Mikko Koivisto and Mathieu
Liedloff and Sebastian Ordyniak and Stefan Szeider},
 booktitle = {Proceedings of the Twenty-Sixth AAAI Conference on
Artificial Intelligence, July 22-26, 2012, Toronto,
Ontario, Canada},
 editor = {J{ö}rg Hoffmann and Bart Selman},
 publisher = {AAAI Press},
 title = {On Finding Optimal Polytrees},
 year = {2012}
}