"1999 Reentries"(PDF). The Aerospace Corporation, Center for Orbital and Reentry Debris Studies. Archived from the original(PDF) on 2005-01-22. Retrieved 2007-12-06.
arxiv.org
Molkov, S.V., Grebenev, S.A., Pavlinsky, M.N., Sunyaev. "GRANAT/ART-P OBSERVATIONS OF GX3+1: TYPE I X-RAY BURST AND PERSISTENT EMISSION", Mar 1999. 4pp. arXiv e-Print (astro-ph/9903089v1).
"1999 Reentries"(PDF). The Aerospace Corporation, Center for Orbital and Reentry Debris Studies. Archived from the original(PDF) on 2005-01-22. Retrieved 2007-12-06.