@article{701700,
     title = {Crystallizing patterns of BGG sequences},
     booktitle = {Proceedings of the 21st Winter School "Geometry and Physics"},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {2002},
     pages = {[233]-243},
     mrnumber = {MR1972438},
     zbl = {1185.17016},
     url = {http://dml.mathdoc.fr/item/701700}
}

Somberg, Petr. Crystallizing patterns of BGG sequences, dans Proceedings of the 21st Winter School "Geometry and Physics", GDML_Books,  (2002), pp. [233]-243. http://gdmltest.u-ga.fr/item/701700/