Daniel Král Riste Skrekovski Martin Tancer Construction of Large Graphs with No Optimal Surjective L(2, 1)-Labelings. 536-543 2006 20 SIAM J. Discrete Math. 2 http://dx.doi.org/10.1137/050623061 db/journals/siamdm/siamdm20.html#KralST06