@article{YangZhang1988,
  author    = {{Yang, Zhi and Zhang, Zhongfu}},
  title     = {{Kakutani conjecture and graph theory representation of the black hole problem}},
  journal   = {{Nature Magazine [Zi ran za zhi (Shanghai)]}},
  year      = {{1988}},
  volume    = {{11}},
  pages     = {{453-456}},
}