LIGO-Virgo S190421ar: AGILE MCAL observations. Ursi, A. ; Cardillo, M. ; Tavani, M. ; Casentini, C. ; Piano, G. ; Lucarelli, F. ; Pittori, C. ; Verrecchia, F. ; Bulgarelli, A. ; Parmiggiani, N. ; Pilia, M. ; Longo, F. Abstract Publication: GRB Coordinates Network Pub Date: 2019 Bibcode: 2019GCN.24140....1U