1. Dabbert S Lippert C Schulz T Zorn A Economic analysis of certification systems for organic food and farming at EU level http://orgprints.org/view/projects/conference.html
2. Stolze M Hartmann M Moschitz H Report on total costs of three organic certification systems in six European countries with particular focus on organic supply http://www.certcost.org/Lib/CERTCOST/Deliverable/D21_B.pdf 2012
3. Zanoli R Affidabilità ed efficacia del sistema nazionale di controllo e globalizzazione dei mercati, atti del seminario “La certificazione dei prodotti biologici nel mercato globale,” Bologna 25-26 March 2010 http://ebookbrowse.com/univpm-raffaele-zanoli-pdf-d141921316 2011