@article{MM2_1978__26_154591,
     author = {Moritz Armsen},
     title = {Variational theory of {Riemannian} subspaces.},
     journal = {Manuscripta mathematica},
     pages = {315--330},
     year = {1978},
     volume = {26},
     zbl = {0396.53012},
     url = {http://geodesic.mathdoc.fr/item/MM2_1978__26_154591/}
}