@article{10_4153_CMB_1981_016_1,
     author = {Lyndon, R. C. and Wicks, M. J.},
     title = {Commutators in {Free} {Groups}},
     journal = {Canadian mathematical bulletin},
     pages = {101--106},
     year = {1981},
     volume = {24},
     number = {1},
     doi = {10.4153/CMB-1981-016-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1981-016-1/}
}