1. Ailon, N., Charikar, M., Newman, A.: Aggregating inconsistent information: Ranking and Clustering. Journal of the ACM 55(5), Article 23 (2008)
2. Bang-Jensen, J., Gutin, G.: Digraphs: Theory, Algorithms and Applications, 2nd edn. Springer, London (2006)
3. Berger, B., Shor, P.W.: Approximation algorithms for the maximum acyclic subgraph problem. In: Proc. First ACM-SIAM Symposium on Discrete Algorithms, pp. 236–243 (1990)
4. Dinur, I., Safra, S.: On the hardness of approximating minimum vertex cover. Annals of Mathematics 162, 439–485 (2005)
5. Eades, P., Lin, X.: A Heuristic for the Feedback Arc Set Problem. Australasian Journal of Combinatorics 12, 15–25 (1995)