@article{AM2_1976__14_136564,
     author = {Richard Friedlander},
     title = {Sequences in {non-Abelian} groups with distinct partial products.},
     journal = {Aequationes mathematicae},
     pages = {59--66},
     year = {1976},
     volume = {14},
     zbl = {0325.20020},
     url = {http://geodesic.mathdoc.fr/item/AM2_1976__14_136564/}
}