@article{SLC_1991_26_a4,
     author = {B. Lulek},
     title = {Impurities in the {Heisenberg} {Magnet} and the {General} {Recipe} of {Weyl}},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1991},
     volume = {26},
     url = {http://geodesic.mathdoc.fr/item/SLC_1991_26_a4/}
}