@article{CMH_1964__39_139287,
     author = {Ernst Alfred Ruh},
     title = {On teh {Automorphism} group of a {G-structure.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {189--204},
     year = {1964},
     volume = {39},
     url = {http://geodesic.mathdoc.fr/item/CMH_1964__39_139287/}
}