@article{SLC_1987_18_a18,
     author = {Ulrich Oberst},
     title = {(Co)-homologie von {Graphen} and {Invarianten}},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1987},
     volume = {18},
     url = {http://geodesic.mathdoc.fr/item/SLC_1987_18_a18/}
}