@article{SLC_1991_26_a5,
     author = {T. Lulek and W. Florek},
     title = {Gauge {Symmetries} in the {Heisenberg} {Model} of a {Magnet}},
     journal = {S\'eminaire lotharingien de combinatoire},
     publisher = {mathdoc},
     volume = {26},
     year = {1991},
     url = {http://geodesic.mathdoc.fr/item/SLC_1991_26_a5/}
}