Emilio Di Giacomo Walter Didimo Giuseppe Liotta Henk Meijer Francesco Trotta Stephen K. Wismath k-colored Point-set Embeddability of Outerplanar Graphs. 29-49 2008 12 J. Graph Algorithms Appl. 1 http://jgaa.info/accepted/2008/DiGiacomo+2008.12.1.pdf db/journals/jgaa/jgaa12.html#GiacomoDLMTW08