1. Experiments to determine the conditions under which “specific” bacteria derived from sewage may be present in the air of ventilating pipes, drains, inspection chambers, and sewers;Horrocks;Public Health,1907
2. Report of the medical officer to the local government board: bacteria of sewer air;Andrewes;Br Med J,1911
3. Airborne microorganisms: occurrance and control;Jessen,1955
4. A slit sampler for collecting and counting air-borne bacteria;Bourdillon;J Hyg (Lond),1941
5. On air-borne infection. Study II: droplets and droplet nuclei;Wells;Am J Hyg,1934