@article{ND_2007_3_4_a2,
     author = {R. F. Shaimuratov},
     title = {On the frequency of recurrence},
     journal = {Russian journal of nonlinear dynamics},
     pages = {401--410},
     publisher = {mathdoc},
     volume = {3},
     number = {4},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ND_2007_3_4_a2/}
}