Philip N. Klein, R. Ravi. When cycles collapse: A general approximation technique for constrained two-connectivity problems. In Giovanni Rinaldi, Laurence A. Wolsey, editors, Proceedings of the 3rd Integer Programming and Combinatorial Optimization Conference, Erice, Italy, April 29 - May 1, 1993. pages 39-55, CIACO, 1993.
Abstract is missing.