@article{GT_1998_2_1_a1,
     author = {Scott, Peter},
     title = {The symmetry of intersection numbers in group theory},
     journal = {Geometry & topology},
     pages = {11--29},
     publisher = {mathdoc},
     volume = {2},
     number = {1},
     year = {1998},
     doi = {10.2140/gt.1998.2.11},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/gt.1998.2.11/}
}