1. ADENE (2010). [NEEAP—2009 Implementation report]. PNAEE—Relatório Nacional de Execução 2009. June 2010. Portuguese Energy Agency, Lisbon, Portugal (in Portuguese). http://www.adene.pt/pt-pt/PNAEE/Documents/Relatrio_Impactos_PNAEE_2009_1_6_2010_2.pdf . Accessed 9 June 2011.
2. APA. (2006). PNAC. [National Climate Change Programme]. Programa Nacional para as Alterações Climáticas. Lisbon: Portuguese Environment Agency (in Portuguese).
3. APA (2011). Portuguese National Inventory Report on Greenhouse Gases 1990–2009. Portuguese Environment Agency. Lisbon, Portugal. [ http://www.apambiente.pt/politicasambiente/Ar/InventarioNacional/Documents/NIR_20110415_v20110515.pdf ]. Accessed 7 June 2011.
4. de Groot, H., Verhoef, E., & Nijkamp, P. (2001). Energy savings by firms: decision-making, barriers and policies. Energy Economics, 23, 717–740.
5. DGEG (2010). National Action Plan for Renewable Energy Within the Directive 2009/28/EC—Final version. (Plano Nacional de Acção Para as Energias Renováveis ao Abrigo da Directiva 2009/28/CE—Versão Final). Portuguese Republic. October 2010, Lisbon, Portugal.