Hitoshi Suzuki Chiseko Yamanaka Takao Nishizeki Parallel Algorithms for Finding Steiner Forests in Planar Graphs. 458-467 1990 conf/sigal/1990 SIGAL International Symposium on Algorithms db/conf/sigal/sigal1990.html#SuzukiYN90 http://dx.doi.org/10.1007/3-540-52921-7_95