1. Altieri, B., Schartel, N., Santos, M., Tomas, L., Guainazzi, M., Piro, L. & Parmar, A. 2000, GCN Circ. 869 (http://gcn.gsfc.nasa.gov/gcn/gcn3/869.gcn3)
2. Discovery of a Redshifted Iron K Line in the X-Ray Afterglow of GRB 000214
3. Burud, I., Rhoads, J., Fruchter A. & Hjorth J. 2001, GCN Circ. 1213 (http://gcn.gsfc.nasa.gov/gcn/gcn3/1213.gcn3)
4. Discovery of an X-ray afterglow associated with the γ-ray burst of 28 February 1997
5. H I in the Galaxy