@article{ModalWorlds,
  author    = {Roland Backhouse and
               Henk Doornbos and
               Roland Gl{\"{u}}ck and
               Jaap van der Woude},
  title     = {Components and acyclicity of graphs. An exercise in combining precision with concision},
  journal   = {Journal of Logical and Algebraic Methods in Programming},
  volume    = {124},
  year      = {2021},
  url       = {https://www.sciencedirect.com/science/article/pii/S2352220821000936},
  doi       = {10.1016/j.jlamp.2021.100730}
}