Hans-Joachim Böckenhauer Dirk Bongartz Juraj Hromkovic Ralf Klasing Guido Proietti Sebastian Seibert Walter Unger On k-connectivity problems with sharpened triangle inequality. 605-617 2008 6 J. Discrete Algorithms 4 http://dx.doi.org/10.1016/j.jda.2008.03.003 db/journals/jda/jda6.html#BockenhauerBHKPSU08