1. European Parliament regulation No 305/2011 laying down harmonized conditions for the marketing of construction products;CPR 305/2011,2011
2. DDEP website, Laboratoire National Henri Becquerel http://www.nucleide.org/DDEP_WG/DDEPdata_by_Z.htm, consulted in March and April of 2016.
3. Radiation Protection 112 Radiological Protection Principles Concerning the Natural Radioactivity of Building Materials;European Commission,1999
4. Radiation Protection 122 Practical Use of the Concepts of Clearance and Exemption Part II Application of the Concepts of Exemption and Clearance to Natural Radiation Sources;European Commission,2001