@InProceedings{l06-p629-640, AUTHOR = {James King}, TITLE = {A 4-Approximation Algorithm for Guarding 1.5-Dimensional Terrains}, YEAR = 2006, BOOKTITLE = {Proc.~of the 7th Latin American Symposium on Theoretical Informatics (LATIN'06)}, ADDRESS = {Valdivia, Chile}, PAGES = {629--640}, KEYWORDS = {}}