@article{IM2_1992_38_1_a0,
     author = {I. K. Babenko and S. A. Bogatyi},
     title = {The behaviour of the ndex of periodic points under iterations of a mapping},
     journal = {Izvestiya. Mathematics },
     pages = {1--26},
     publisher = {mathdoc},
     volume = {38},
     number = {1},
     year = {1992},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1992_38_1_a0/}
}