@article{IM_1983__71_143004,
     author = {John R. Stallings},
     title = {Topology of {Finite} {Graphs.}},
     journal = {Inventiones mathematicae},
     pages = {551--566},
     publisher = {mathdoc},
     volume = {71},
     year = {1983},
     zbl = {0521.20013},
     url = {http://geodesic.mathdoc.fr/item/IM_1983__71_143004/}
}