PAÍS VASCO / BASQUE COUNTRY (Spain), October 2013. GPS-Lehendakaritza

http://www.lehendakaritza.ejgv.euskadi.net/contenidos/informe_estudio/o_13sv53_previsiones/eu_13sv53pr/adjuntos/13sv53_previsiones.pdf

http://en.wikipedia.org/wiki/List_of_political_parties_in_the_Basque_Country