1. AmericanPublicHealthAssociation, AmericanWaterWorksAssociationWaterPollutionControlFederation(1967 ) Standard methods for the examination of water and waste water including bottom sediments and sludges . 13th edition. N.Y. Am. Public Health Ass., pp.874 .
2. A.E. Bailey-Watts(1973 )Observations on the phytoplankton of Loch Leven, Kinross, Scotland. Ph.D. thesis , University of London.