@article{GroetschelWakabayashi1989,
  author    = {Martin Gr{\"o}tschel and Yoshiko Wakabayashi},
  title     = {A cutting plane algorithm for a clustering problem},
  journal   = {Mathematical Programming, Series B},
  volume    = {45},
  pages     = {59 -- 96},
  year        = {1989},
}