@article{10_1017_S2040618500035449,
     author = {Walker, R. G.},
     title = {Non-cancellative power-free groups},
     journal = {Glasgow mathematical journal},
     pages = {207--212},
     year = {1966},
     volume = {7},
     number = {4},
     doi = {10.1017/S2040618500035449},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S2040618500035449/}
}