@article{SLC_1991_26_a2,
     author = {Walter Wenzel},
     title = {\ensuremath{\Delta}-matroids and {Pfaffian} {Forms}},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1991},
     volume = {26},
     url = {http://geodesic.mathdoc.fr/item/SLC_1991_26_a2/}
}