@article{IVM_2003_6_a2,
     author = {E. S. Astapova and N. S. Astapov},
     title = {Some examples of quadratic summation of power series},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {23--27},
     year = {2003},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2003_6_a2/}
}