Valtera

https://science.nasa.gov/heliophysics

https://www.sws.bom.gov.au/IPSHosted/INAG/uag-104/text/bullett1.html

https://gect.ru/atmosphere/ionosphere.html

http://www.radioscanner.ru/info/article60/

https://ru.wikipedia.org/wiki/%D0%98%D0%BE%D0%BD%D0%BE%D0%B3%D1%80%D0%B0%D0%BC%D0%BC%D0%B0

https://studfile.net/preview/5094101/page:7/