@article{JGG_2006_10_1_JGG_2006_10_1_a0,
     author = {J. J. Fowler and E. Gethner },
     title = {Counting {Escher's} m x m {Ribbon} {Patterns}},
     journal = {Journal for geometry and graphics},
     pages = {1--13},
     publisher = {mathdoc},
     volume = {10},
     number = {1},
     year = {2006},
     url = {http://geodesic.mathdoc.fr/item/JGG_2006_10_1_JGG_2006_10_1_a0/}
}