LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient in ASAS-SN observations hours before and after discovery. Shappee, B. J. ; Kochanek, C. S. ; Stanek, K. Z. ; Holmbo, S. ; Franckowiak, A. ; Holoien, T. W. -S. ; Prieto, J. L. ; Dong, S. ; Thompson, T. A. ; Beacom, J. F. Abstract Publication: GRB Coordinates Network Pub Date: 2019 Bibcode: 2019GCN.24313....1S