@article{RCM_2007_41_1_a3,
     author = {Federico Ardila San Francisco State University and San Francisco},
     title = {Semimatroids and their {Tutte} polynomials},
     journal = {Revista colombiana de matematicas},
     pages = {39--66},
     publisher = {mathdoc},
     volume = {41},
     number = {1},
     year = {2007},
     url = {http://geodesic.mathdoc.fr/item/RCM_2007_41_1_a3/}
}