@article{SIGMA_2006_2_a54,
     author = {Natasha D. Popova and Yurii S. Samoilenko},
     title = {On the {Existence} of {Configurations} of {Subspaces} in {a~Hilbert} {Space} with {Fixed} {Angles}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2006},
     volume = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2006_2_a54/}
}