@article{10_2140_agt_2015_15_85,
     author = {Borodzik, Maciej and Friedl, Stefan},
     title = {The unknotting number and classical invariants, {I}},
     journal = {Algebraic and Geometric Topology},
     pages = {85--135},
     year = {2015},
     volume = {15},
     number = {1},
     doi = {10.2140/agt.2015.15.85},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2015.15.85/}
}