Oblinger Childress, Carolyn J. <br/><br/>
Water-quality data-collection activities in Colorado and Ohio :  phase 2 -evaluation of 1984 field and laboratory quality-assurance practices / 
by Carolyn J. Oblinger Childress...[et.al] 
 - Washington D.C :  U.S Government Printing Office,  1989. 
 - vi, 49 p. :  ill 
 - Water supply paper/ U.S. Geological Survey ;  2295 .
<br/><br/> PTSL