@article{SEMR_2011_8_a32,
     author = {S. S. Ibraev},
     title = {The second cohomology groups of simple modules for $G_2$},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {381--396},
     publisher = {mathdoc},
     volume = {8},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2011_8_a32/}
}