@article{EP_2012_36_a7,
     author = {Boris Gurevich and Sergei Komech},
     title = {On evolution of small spheres in the phase space of a dynamical system},
     journal = {ESAIM. Proceedings},
     pages = {68--72},
     publisher = {mathdoc},
     volume = {36},
     year = {2012},
     doi = {10.1051/proc/201236007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1051/proc/201236007/}
}