Boaz Ben-Moshe, Matthew J. Katz, Joseph S. B. Mitchell. A constant-factor approximation algorithm for optimal terrain guarding. In Proceedings of the Sixteenth Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2005, Vancouver, British Columbia, Canada, January 23-25, 2005. pages 515-524, SIAM, 2005. [doi]
Abstract is missing.