1. Testing of HEPA and ventilation filters;Morris;Filtration & Separation,1994
2. FiltrationandIAQ;Wolf;Filtration & Separation,2001
3. Characterisation of HEPA and ULPA filters by proposed new European test methods;Wepfer,1995
4. Method for the manufacture of smoke filters or collector filters;Hansen,1931
5. The Hansen filter;Feltham;Filtration & Separation,1979