1. Standard Methods for the Examination of Water and Wastewater;APHA,1985
2. Precision of Test Methods, Part 1. Guide to the Determination of Repeatability and Reproducibility of a Standard Test Method;British Standards Institute,1987
3. Methods for the Examination of Waters and Associated Materials: Biochemical Oxygen Demand 1981;Department of the Environment,1983
4. Biochemical oxygen demand: interlaboratory precision test;Fitzmaurice,1987
5. Biochemical oxygen demand: a proposed standard for Irish laboratories;Fitzmaurice,1987