Michael Elkin, Guy Kortsarz. Approximation Algorithm for Directed Telephone Multicast Problem. In Jos C. M. Baeten, Jan Karel Lenstra, Joachim Parrow, Gerhard J. Woeginger, editors, Automata, Languages and Programming, 30th International Colloquium, ICALP 2003, Eindhoven, The Netherlands, June 30 - July 4, 2003. Proceedings. Volume 2719 of Lecture Notes in Computer Science, pages 212-223, Springer, 2003. [doi]
Abstract is missing.