1. The stacked filter unit revisited;Cahill,1990
2. Particle collection efficiencies of air sampling cyclones: an empirical theory;Chan;Envir. Sci. Technol,1977
3. Regional patterns in particulate matter from the National Park Service network, June 1982 to May 1986;Eldred,1978
4. Sampling techniques for fine particle/visibility studies in the National Park Service network;Eldred,19786
5. Measurements of fine particles and their chemical composition in the IMPROVE/NPS networks;Eldred,1990