@article{GT_1998_2_1_a8,
     author = {Birman, Joan S and Hirsch, Michael D},
     title = {A new algorithm for recognizing the unknot},
     journal = {Geometry & topology},
     pages = {175--220},
     publisher = {mathdoc},
     volume = {2},
     number = {1},
     year = {1998},
     doi = {10.2140/gt.1998.2.175},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/gt.1998.2.175/}
}