1. Pollen Content of the Air;Duke;J. A. M. A,1928
2. System for Intensive Pollen Survey with Report of Results in Chicago;Koessler;J. A. M. A,1926
3. Study of Atmospheric Pollen and Botanic Flora of East Shore of San Francisco Bay;Rowe;J. Lab. & Clin. Med,1928
4. Hay Fever Pollen in Upper Air;Scheppegrell;M. J. & Rec,1925
5. Factors Which Determine Pollen Content of Air;Balyeat;J. Lab. & Clin. Med,1927