What did ASCA see in the GRB 970828 afterglow? A. Yoshida, M. Namiki, C. Otani, N. Kawai, T. Murakami, Y. Ueda, R. Shibata and S. Uno Astron. Astrophys. Suppl. Ser., 138 3 (1999) 433-434 Published online: 15 September 1999 DOI: 10.1051/aas:1999297