1) Collins, C. H. and P. M. Lyne (1970) Mi crobiological Method, 3rd ed. Butterworth & Co. Publishers Ltd., London and University Park Press, Boltimore, 363-368.
2) Mailman, W. L. and W. Litsky (1951) Survival of selected enteric organisms in various types of soil. Am. J. Public Health, 41, 38-44.
3) Litsky, W., W. L. Mallman and C. W. Fifield (1955) Comparison of the most probable number of Escherichia coli and Enterococci in river waters. Am. J. Public Health. 45, 1049-1053.
4) European Communities (1976) Hygiene of bathing water. Council Directive No. 76/160/EEC. Digest of Health Legislation 27, 709-717.
5) The National Technical Advisory Committee (1968) Criteria for primary contact recreation, In Water Quality Criteria, Report of the National Technical Advisory Committee to the Secretary of Interior, 11-14.