@article{10_1017_S0017089502020025,
     author = {Clifford, Andrew},
     title = {A {Class} of {Exponent-Sum} {Two} {Equations} {Over} {Groups}},
     journal = {Glasgow mathematical journal},
     pages = {201--207},
     year = {2002},
     volume = {44},
     number = {2},
     doi = {10.1017/S0017089502020025},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089502020025/}
}