@article{10_4153_CMB_1990_057_3,
     author = {Edmunds, Charles C. and Rosenberger, Gerhard},
     title = {Powers of {Genus} two in {Free} {Groups}},
     journal = {Canadian mathematical bulletin},
     pages = {342--344},
     year = {1990},
     volume = {33},
     number = {3},
     doi = {10.4153/CMB-1990-057-3},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1990-057-3/}
}