@inproceedings{GroetschelJuengerReinelt1985, author = {Martin Gr{\"o}tschel and Michael J{\"u}nger and Gerhard Reinelt}, title = {Acyclic subdigraphs and linear orderings}, booktitle = {Graphs and Order. The Role of Graphs in the Theory of Ordered Sets and its Applications, Proceedings of NATO ASI, Ser. C 147, Banff/Canada 1984}, editor = {Ivan Rival}, pages = {217 -- 264}, year = {1985}, }