@article{10_2140_agt_2008_8_803,
     author = {Sakasai, Takuya},
     title = {The {Magnus} representation and higher-order {Alexander} invariants for homology cobordisms of surfaces},
     journal = {Algebraic and Geometric Topology},
     pages = {803--848},
     year = {2008},
     volume = {8},
     number = {2},
     doi = {10.2140/agt.2008.8.803},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2008.8.803/}
}