@article{JMAG_2001_8_2_a3,
     author = {Ya. M. Dymarskii},
     title = {The manifolds of self-adjoint operators with multiple eigenvalues},
     journal = {\v{Z}urnal matemati\v{c}eskoj fiziki, analiza, geometrii},
     pages = {148--157},
     year = {2001},
     volume = {8},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/JMAG_2001_8_2_a3/}
}