@article{10_4153_CMB_1970_082_7,
     author = {Gupta, Chander Kanta},
     title = {On {Free} {Groups} of the {Variety} {AN} 2 \ensuremath{\wedge} {N} 2 {A}},
     journal = {Canadian mathematical bulletin},
     pages = {443--446},
     year = {1970},
     volume = {13},
     number = {4},
     doi = {10.4153/CMB-1970-082-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1970-082-7/}
}