@article{SM_2007_198_2_a0,
     author = {B. N. Apanasov and I. Kim},
     title = {Cartan angular invariant and deformations of rank~1 symmetric spaces},
     journal = {Sbornik. Mathematics},
     pages = {147--169},
     publisher = {mathdoc},
     volume = {198},
     number = {2},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2007_198_2_a0/}
}