Erik D. Demaine, MohammadTaghi Hajiaghayi, Philip N. Klein. Node-Weighted Steiner Tree and Group Steiner Tree in Planar Graphs. In Susanne Albers, Alberto Marchetti-Spaccamela, Yossi Matias, Sotiris E. Nikoletseas, Wolfgang Thomas, editors, Automata, Languages and Programming, 36th International Colloquium, ICALP 2009, Rhodes, Greece, July 5-12, 2009, Proceedings, Part I. Volume 5555 of Lecture Notes in Computer Science, pages 328-340, Springer, 2009. [doi]
Abstract is missing.