Toru Hasunuma, Toshimasa Ishii, Hirotaka Ono, Yushi Uno. The (2, 1)-Total Labeling Number of Outerplanar Graphs Is at Most Δ + 2. In Costas S. Iliopoulos, William F. Smyth, editors, Combinatorial Algorithms - 21st International Workshop, IWOCA 2010, London, UK, July 26-28, 2010, Revised Selected Papers. Volume 6460 of Lecture Notes in Computer Science, pages 103-106, Springer, 2010. [doi]
Abstract is missing.