@article{MAN_1976__221_162840,
     author = {Jean-Pierre Bourguignon},
     title = {Sur les g\'eod\'esiques ferm\'ees des vari\'et\'es quaternionniennes de dimension 4.},
     journal = {Mathematische Annalen},
     pages = {153--166},
     publisher = {mathdoc},
     volume = {221},
     year = {1976},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/item/MAN_1976__221_162840/}
}