Meena Mahajan, Prajakta Nimbhorkar, Kasturi R. Varadarajan. The Planar k-Means Problem is NP-Hard. In Sandip Das, Ryuhei Uehara, editors, WALCOM: Algorithms and Computation, Third International Workshop, WALCOM 2009, Kolkata, India, February 18-20, 2009. Proceedings. Volume 5431 of Lecture Notes in Computer Science, pages 274-285, Springer, 2009. [doi]
Abstract is missing.