. . "Observations"@en . . . . . "Solar-geophysical activity reports for Stip Interval XV : 12-21 February 1984 Ground Level Event and Stip Interval XVI : 20 April-4 May 1984 Forbush Decrease"@en . . . . . . . . . "Solar-geophysical activity reports for Stip Interval XV 12-21 February 1984 Ground Level Event and Stip Interval XVI : 20 April-4 May 1984 Forbush Decrease"@en . . .