TY JOUR TI Pitch-angle anisotropy and differential rigidity spectra of cosmic rays during GLE on May 2 and 6, 1998 KW cosmic rays KW ground level enhancement KW anisotropy KW rigidity spectrum JO Solar-Terrestrial Physics AU Lukovnikova, A.A. AU Sdobnov, V.E. PY 2022 IS 8 PB INFRA-M Academic Publishing LLC.