H. Alt, K. Buchin, S. Chaplick, O. Cheong, P. Kindermann, C. Knauer, and F. Stehn. Proceedings of the 28th International Symposium on Algorithms and Computation (ISAAC'17), 92, page 4:1--4:12. Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, (December 2017)