1. Agung volcano news & activity updates: Agung volcano Volcanic Ash Advisory: CONTINUOUS VA EMISSION TO FL260 EXTD S/SE OBS VA DTG: 26/0120Z. https://www.volcanodiscovery.com/agung/news/66178/Agung-volcano-Volcanic-Ash-Advisory-CONTINUOUS-VA-EMISSION-TO-FL260-EXTD-SSE-OBS-VA-DTG-260120Z.html.
2. Agung volcano news & activity updates: Gunung Agung volcano (Bali, Indonesia): eruption has begun. –https://www.volcanodiscovery.com/agung/news/66181/Gunung-Agung-volcano-Bali-Indonesia-eruption-has-begun.html.
3. Ash Plume across the North Atlantic. NASA Earth Observatory. http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=43670.
4. Deadly Eruption Rocks Guatemala. NASA Earth Observatory. https://earthobservatory.nasa.gov/images/92235/a-deadly-eruption-rocks-guatemala.
5. Space weather: risk factors for global navigation satellite systems;Demianov;Solar-Terrestrial Phys.,2021