@article{JGG_2013_17_1_JGG_2013_17_1_a6,
     author = {M. Zawidzki and K. Nishinari },
     title = {Modular {Pipe-Z} {System} for {Three-Dimensional} {Knots}},
     journal = {Journal for geometry and graphics},
     pages = {81--87},
     publisher = {mathdoc},
     volume = {17},
     number = {1},
     year = {2013},
     url = {http://geodesic.mathdoc.fr/item/JGG_2013_17_1_JGG_2013_17_1_a6/}
}