Publications by European Aggregates Association (UEPG) and other international guilds and associations.
Boletín de información naturaleza y biodiversidad, Comisión Europea (junio 2010).
UEPG Annual Report 2008-2009 (Spanish) http://www.uepg.eu/index.php?pid=7&id=23 (English)
UEPG Annual Report 2007 (Spanish) http://www.uepg.eu/index.php?pid=7 (English)
