@article{IM_1984__76_143116,
     author = {J. Howie and S.J. Pride},
     title = {A spelling theorem for staggered generalized 2-complexes, with applications.},
     journal = {Inventiones mathematicae},
     pages = {55--74},
     publisher = {mathdoc},
     volume = {76},
     year = {1984},
     zbl = {0544.20033},
     url = {http://geodesic.mathdoc.fr/item/IM_1984__76_143116/}
}