@article{IIGUM_2016_17_a0,
     author = {E. N. Galushina},
     title = {On a double series representation of $\pi$},
     journal = {The Bulletin of Irkutsk State University. Series Mathematics},
     pages = {3--11},
     publisher = {mathdoc},
     volume = {17},
     year = {2016},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IIGUM_2016_17_a0/}
}