@article{SLC_1988_19_a10,
     author = {Reinhard Franz},
     title = {Zur {Abz\"ahlung} periodischer {Pflasterungen} der euklidische {Ebene}},
     journal = {S\'eminaire lotharingien de combinatoire},
     publisher = {mathdoc},
     volume = {19},
     year = {1988},
     url = {http://geodesic.mathdoc.fr/item/SLC_1988_19_a10/}
}