1. Agenda 21, the Rio Declaration on Environment and Development, the Statement of Forest Principles, the United Nations Framework Convention on Climate Change and the United Nations Convention on Biological Diversity, United Nations Conference on Environment and Development (UNCED), Rio de Janeiro, 3–14 June 1992.
2. Cembureau, 2014 Activity Report, 2014. http://www.cembureau.be/activityreports (accessed 10.02.16).
3. Cembureau, 2013. Activity Report 2013. http://www.cembureau.be/activityreports (accessed 10.02.16).
4. Cembureau, 2012. Activity Report 2012. http://www.cembureau.be/activityreports (accessed 10.02.16).
5. Fredonia; World Construction Aggregates to 2011 – Demand and Sales Forecasts; Market Share, Market Size, Market leaders, Industry.