@article{MZ_1991__208_3_174313,
     author = {James Howie and Andrew J. Duncan},
     title = {The genus problem for one-relator products of locally indicable groups.},
     journal = {Mathematische Zeitschrift},
     pages = {225--238},
     publisher = {mathdoc},
     volume = {208},
     number = {3},
     year = {1991},
     zbl = {0724.20024},
     url = {http://geodesic.mathdoc.fr/item/MZ_1991__208_3_174313/}
}