@article{MAN_1991__291_1_164887,
     author = {Kouki Taniyama},
     title = {On unknotting operations of two-brigde knots.},
     journal = {Mathematische Annalen},
     pages = {579--590},
     publisher = {mathdoc},
     volume = {291},
     number = {1},
     year = {1991},
     zbl = {0726.57009},
     url = {http://geodesic.mathdoc.fr/item/MAN_1991__291_1_164887/}
}