@article{GDZPPN002105683, title = {Normal-convexity and equations over groups.}, journal = {Inventiones mathematicae}, volume = {93}, year = {1988}, pages = {81-104}, zbl = {0655.20025}, url = {http://dml.mathdoc.fr/item/GDZPPN002105683} }
Brick, Stephen G. Normal-convexity and equations over groups.. Inventiones mathematicae, Tome 93 (1988) pp. 81-104. http://gdmltest.u-ga.fr/item/GDZPPN002105683/