%0 Journal Article %A V. A. Vatutin %A E. E. Dyakonova %A V. A. Topchii %T Critical Galton-Watson branching processes with a~countable set of types and infinite second moments %J Sbornik. Mathematics %D 2021 %P 1-24 %V 212 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/SM_2021_212_1_a0/ %G en %F SM_2021_212_1_a0