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		| Paper: | 
		X-Ray Afterglows and Spectroscopy of Gamma-Ray Bursts | 
	 
	
		| Volume: | 
		312, Third Rome Workshop on Gamma-Ray Bursts in the Afterglow Era | 
	 
	
		| Page: | 
		149 | 
	 
	
		| Authors: | 
		Piro, L. | 
	 
	
	
		| Abstract: | 
		I will review the constraints set by X-ray measurements of afterglows on several issues of GRB, with particular regard to the fireball model, the environment, the progenitor and dark GRB. | 
	 
	
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