@article{MAN_1984__268_182919,
     author = {Patrick Coulton},
     title = {Integral {Invariants} of {Principal} {SO(n)(r)Grouv} {Structures} on {Space} {Forms.}},
     journal = {Mathematische Annalen},
     pages = {265--272},
     publisher = {mathdoc},
     volume = {268},
     year = {1984},
     zbl = {0527.53022},
     url = {http://geodesic.mathdoc.fr/item/MAN_1984__268_182919/}
}