Michael Dinitz, Guy Kortsarz, Ran Raz. Label Cover Instances with Large Girth and the Hardness of Approximating Basic k-Spanner. In Artur Czumaj, Kurt Mehlhorn, Andrew M. Pitts, Roger Wattenhofer, editors, Automata, Languages, and Programming - 39th International Colloquium, ICALP 2012, Warwick, UK, July 9-13, 2012, Proceedings, Part I. Volume 7391 of Lecture Notes in Computer Science, pages 290-301, Springer, 2012. [doi]
Abstract is missing.