@article{SLC_1996_36_a5,
     author = {Ulrich Kr\"uger},
     title = {An extreme point theorem for ordered polymatroids on chain orders},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1996},
     volume = {36},
     url = {http://geodesic.mathdoc.fr/item/SLC_1996_36_a5/}
}