@article{SLC_1984_10_a15,
     author = {Martin Gr\"otschel},
     title = {Characterisations of {Perfect} {Graphs}},
     journal = {S\'eminaire lotharingien de combinatoire},
     publisher = {mathdoc},
     volume = {10},
     year = {1984},
     url = {http://geodesic.mathdoc.fr/item/SLC_1984_10_a15/}
}