@article{10_2140_agt_2009_9_305,
     author = {Kent, Richard Peabody},
     title = {Intersections and joins of free groups},
     journal = {Algebraic and Geometric Topology},
     pages = {305--325},
     year = {2009},
     volume = {9},
     number = {1},
     doi = {10.2140/agt.2009.9.305},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2009.9.305/}
}