@article{MM2_1995__88_1_156129,
     author = {Riccardo Benedetti and Carlo Petronio},
     title = {A finite graphic calculus for 3-manifolds.},
     journal = {Manuscripta mathematica},
     pages = {291--310},
     publisher = {mathdoc},
     volume = {88},
     number = {1},
     year = {1995},
     zbl = {0856.57009},
     url = {http://geodesic.mathdoc.fr/item/MM2_1995__88_1_156129/}
}