@article{Язев2021complexes,
author={Язев, С.А. and Ульянова, М.М. and Исаева, Е.С.},
title={Complexes of activity on the Sun in solar cycle 21},
journal={Solar-Terrestrial Physics},
publisher={Институт солнечно-земной физики СО РАН},
year={2021},
pages={3-9},
volume={7},
issue={4},
}