@article{10_37236_1298,
     author = {Gary Gordon},
     title = {A \(\beta\) invariant for greedoids and antimatroids},
     journal = {The electronic journal of combinatorics},
     year = {1997},
     volume = {4},
     number = {1},
     doi = {10.37236/1298},
     zbl = {0885.05049},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/1298/}
}