Editorial

Readers are welcome to the second issue of volume 18 of the Journal of the Brazilian Computer Society. This is a special issue with full papers selected from those presented at (volume 7, n. 3), on the contributions of Professor Szwarc-fiter to graph theory and computer science. The reason for reprinting it in this issue is twofold. Only recently we realized the printed version of the original publication truncated the final two pages of the article. We take the opportunity brought about by this special issue to make sure researchers in graph theory and applications gain access to the full version of that paper. It is also reprinted in celebration of Professor Szwarcfiter 70th birthday, as an acknowledgment of his continuing important contributions to the field.