GRB981220, optical observations. Pedersen, H. ; Lindgren, B. ; Hjorth, J. ; Andersen, M. I. ; Jaunsen, A. O. ; Sollerman, J. ; Smoker, J. ; Mooney, C. Abstract Publication: GRB Coordinates Network Pub Date: 1999 Bibcode: 1999GCN...192....1P