László A. Végh, András A. Benczúr. Primal-dual approach for directed vertex connectivity augmentation and generalizations. In Proceedings of the Sixteenth Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2005, Vancouver, British Columbia, Canada, January 23-25, 2005. pages 186-194, SIAM, 2005. [doi]
Abstract is missing.