00696naa#a2200205#i#450# EN\\bibl\42233 20260315094927.7 2500-0535 20211220b2021####ek#y0engy0150####ca ENG RU On the group velocity of whistling atmospherics Journal article Irkutsk Institute of Solar-Terrestrial Physics SB RAS 2021 3 с. Journal article local Геология. Геологические и геофизические науки. 55 ENG Guglielmi Anatol Vladimirovich Klain Boris Icikovich Potapov Alexander Sergeevich iszf.editorum.ru