1. Is pH Paper an Acceptable, Low-Cost Alternative to the Blood Gas Analyzer for Determining Pleural Fluid pH? 
Emil P. Lesho, DO, Bernard J. Roth, MD 
CHEST 
Volume 112, Issue 5, Pages (November 1997)
DOI: /chest
Copyright © 1997 The American College of Chest Physicians Terms and Conditions

2. FIGURE 1
Regression plot showing lack of correlation between the two measurement techniques.
CHEST  , DOI: ( /chest )
Copyright © 1997 The American College of Chest Physicians Terms and Conditions