@article{SIGMA_2008_4_a11,
     author = {Chitta Ranjan Das and Larisa V. Laperashvili},
     title = {Preon {Model} and {Family} {Replicated} $E_6$ {Unification}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2008},
     volume = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2008_4_a11/}
}