1. B. Neuffer, M. Laney, Alternative Control Techniques Document Update – NOx Emissions from New Cement Kilns. U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division Research Triangle Park, North Carolina, (2007).
2. International Organisation for Standardisation, ISO 14040, Environmental Management—Life Cycle Assessment—Principles and Framework, 2006, Geneva.
3. International Organisation for Standardisation, ISO 14041, Environmental Management—Life Cycle Assessment—Goal and Scope Definition and Inventory Analysis, 1998, Geneva.
4. International Organisation for Standardisation, ISO 14042, Environmental Management, Life Cycle Assessment, Life Cycle Assessment, 2000, Geneva.
5. International Organization for Standardization. ISO14043: Enviornmental management-Life cycle assessment-Life cycle interpretation. 2000, Geneva.