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		| Paper: | 
		Searching for Massive Protostars: a BIMA Survey of High-Mass Precursors | 
	 
	
		| Volume: | 
		267, Hot Star Workshop III: the Earliest Stages of Massive Star Birth | 
	 
	
		| Page: | 
		371 | 
	 
	
		| Authors: | 
		Gibb, A. G.; Wyrowski, F.; Mundy, L. G.; Thompson, M. A. | 
	 
	
	
		| Abstract: | 
		We have observed a sample of 9 ultracompact HII regions which show extended submillimetre dust emission in the 3-mm lines of N2H+, CH3OH, C34S, CH3CN, C18O and 3-mm continuum. We detected 50 massive cores, most previously unknown and most with no embedded infrared or radio sources. Of those mapped in both N2H+ and C18O, 21% have weak or no C18O emission. These cores show evidence for CO depletion, and may therefore be undergoing collapse. | 
	 
	
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