@article{Gordon97,
  title = {A beta Invariant for Greedoids and Antimatroids},
  author = {Gary Gordon},
  year = {1997},
  url = {http://www.combinatorics.org/Volume_4/Abstracts/v4i1r13.html},
  researchr = {https://researchr.org/publication/Gordon97},
  cites = {0},
  citedby = {0},
  journal = {Electr. J. Comb.},
  volume = {4},
  number = {1},
}