1. Determination of sulfuric acid, total particle-phase acidity and nitric acid in ambient air;Appel;Final Report to the California Air Resources Board,1979
2. Improvement and evaluation of methods for sulfate analysis;Appel;Final Report, EPA Grant No. 805-447-1,1979
3. Simultaneous nitric acid, particulate nitrate and acidity measurements in ambient air;Appel;Atmospheric Environment,1980
4. Development of a portable device to collect sulfuric acid aerosol;Barrett;EPA Report 600/2-77-027,1977
5. Man-made airborne acidity and its determination;Brosset;Atmospheric Environment,1978