@article{IM_1994__117_1_144220,
     author = {Warren Dicks},
     title = {Equivalence of the strengthened {Hanna} {Neumann} conjecture and the amalgamated graph conjecture.},
     journal = {Inventiones mathematicae},
     pages = {373--390},
     publisher = {mathdoc},
     volume = {117},
     number = {1},
     year = {1994},
     zbl = {0809.05055},
     url = {http://geodesic.mathdoc.fr/item/IM_1994__117_1_144220/}
}