1. American Public Health Association. 1976. Standard methods for the examination of water and wastewater 14th ed. American Public Health Association Washington D.C.
2. Viability of Iyophilized microorganisms after storage. Antonie van Leeuwenhoek J;Anthieunisse J.;Microbiol. Serol.,1973
3. The role of quality control in the clinical bacteriology laboratory;Barry A. L.;Am. J. Med. Technol.,1968
4. Proficiency test specimens for water bacteriology;Cada R. L;Appl. Microbiol.,1975
5. Salt-a preservative for bacterial cultures;Chance H. L;J. Bacteriol.,1963