1. VDZ, Activity Report 2007–2009; 2009,http://www.vdz-online.de. Obtained April 20, 2011.
2. Cembureau, Activity Report 2008;http://www.cembureau.be. Obtained April 20, 2011.
3. BP Statistical Review of World Energy; June 2009,http://www.bp.com. Obtained April 20, 2011.
4. Cembureau, Alternative Fuels in Cement Manufacture; 1997, http://www.cembureau.be. Obtained April 20, 2011.
5. High-Temperature Release of SO2 from Calcined Cement Raw Materials