1. F. Barahona, M. Grötschel, M. Jünger, and G. Reinelt, Oper. Res. 36, 493–513 (1988).
2. M. Bern and D. Eppstein, in Approximation Algorithms for NP-Hard Problems (PWS Boston, 1997), pp. 296–345.
3. T. N. Bui, S. Chaudhuri, F. T. Leighton, and M. Sipser, Combinatorica 7(2), 171–191 (1987).
4. C. H. Q. Ding, He Xiaofeng, Zha Hongyuan, Gu Ming, H. D. Simon, in Proceedings of IEEE Inter-national Conference on Data Mining, San Jose, California, Nov. 29-Dec. 2, 2001 (IEEE Comput. Soc., Los Alamitos (CA), 2001), pp. 107–114.
5. A. Eisenblätter, in Proceedings of the 9th International IPCO Conference on Integer Programming and Combinatorial Optimization, Cambridge (MA), May 27–29, 2002 (Springer, Berlin, 2002), Lect. Notes Comput. Sci. 2337, 273–290 (2002).