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		| Paper: | 
		The Luminous Variable Stars in M33 | 
	 
	
		| Volume: | 
		388, Mass Loss from Stars and the Evolution of Stellar Clusters | 
	 
	
		| Page: | 
		227 | 
	 
	
		| Authors: | 
		Viotti, R.F.; Polcaro, V.F.; Rossi, C.; Montagni, F.; Norci, L.; Gualandi, R. | 
	 
	
	
		| Abstract: | 
		We present a spectrophotometric study of seven LBVs in M33, and discuss the physical nature of variable stars in the upper H–R diagram. | 
	 
	
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