@article{MZ_1967__95_170655,
     author = {Hermann Heineken and Narain Datt Gupta},
     title = {Groups with a {Two-Variable} {Commutator} {Identity.}},
     journal = {Mathematische Zeitschrift},
     pages = {276--287},
     publisher = {mathdoc},
     volume = {95},
     year = {1967},
     zbl = {0143.03801},
     url = {http://geodesic.mathdoc.fr/item/MZ_1967__95_170655/}
}