@article{Poljak87,
  title = {Transformations on Graphs and Convexity},
  author = {Svatopluk Poljak},
  year = {1987},
  url = {http://www.complex-systems.com/abstracts/v01_i05_a07.html},
  researchr = {https://researchr.org/publication/Poljak87},
  cites = {0},
  citedby = {0},
  journal = {Complex Systems},
  volume = {1},
  number = {5},
}