@article{10_37236_1828,
     author = {Axel Hultman},
     title = {Directed subgraph complexes},
     journal = {The electronic journal of combinatorics},
     year = {2004},
     volume = {11},
     number = {1},
     doi = {10.37236/1828},
     zbl = {1060.05038},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/1828/}
}