1. OECD. 2002. Recommendation of the council on improving the environmental performance of public procurement. C(2002)3. Available from: http://webdomino1.oecd.org/horizontal/oecdacts.nsf/linkto/C(2002)3.
2. Ecolabeling: actual effects of selected programs,1997
3. ISO 14020:2000. Environmental labels and declaration—General principles.
4. ISO 14021:1999. Environmental labels and declaration—Self-declared environmental claims (Type II environmental labeling).
5. ISO 14024:1999. Environmental labels and declaration—Type I environmental labeling—Principles and procedures.