@article{DvorakOrdyniakSzeider12,
 author = {Dvor{\'a}k and Sebastian Ordyniak and
Stefan Szeider},
 doi = {10.1016/j.artint.2012.03.002},
 journal = {Artificial Intelligence},
 pages = {157-173},
 title = {Augmenting tractable fragments of abstract
argumentation},
 volume = {186},
 year = {2012}
}