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2. American Hospital Association. 1979. Infection control in the hospital 4th ed. American Hospital Association Chicago.
3. A cooperative microbiological evaluation of floor-cleaning procedures in hospital patient rooms;American Public Health Association Committee on Microbial Contamination of Surfaces, Laboratory Section.;Health Lab. Sci.,1970
4. Bond R. G. M. M. Halbert K. M. Keenan H. D. Putnam 0. R. Ruschmeyer and D. Vesley. 1963. Development of a method for microbial sampling of surfaces with special reference to reliability. University Health Service and School of Public Health University of Minnesota Minneapolis.
5. CDC guidelines on infection control;Centers for Disease Control.;Infect. Control,1981