1. 3) NAFA Guide to Air Filtration. (2001)
2. 4) HARSTAD J. Bruce. Penetration of Submicron Ti Bacteriophage Aerosols and Bacterial Aerosols through Commercial Air Filter. 9^<th> Air AEC Air Cleaning Conference, Harvard University School of Public Health, September 13-16, 1966. (1966)
3. 5) Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size, ASHRAE, 1999. ASHR AE/ANSI Standard 52.2-1999.
4. 6) YANAGI U. A Study on the Filtration Efficiency of an Air Filter over Airborne Bacteria and Fungi vs Elapsed Time. Proceeding of Healthy buildings 2006. (2006) vol.4, p.479-482.
5. 9) OFFERMAN F. J. Performance of air cleaners in a residential forced air system. ASHRAE J.. vol.34, no.7, p.51-57.