1. ASTM Designation: D3972-90 (available on the site of ASTM).
2. Balbou, 2001. Main principles and norms for radioprotection in Republic of Bulgaria, edition 2000.
3. BG Government et al, 1989. Standards-presentation of Environment. Quality of water. Determination of uranium in water, Bulgarian national standard, 1983.
4. National Primary Drinking Water Regulations; Analytical Methods for Radionuclides,1997