Standard basque : a progressive grammar / Rudolf P.G. de Rijk ; [prólogo, Pello Salaburu]

Cambridge, Mass.[achusetts] : The Mit Press , [2008

The challenge of a bilingual society in the Basque Country / edited by Pello Salaburu and Xabier Alberdi

Reno : Center for Basque Studies, University of Nevada, Reno ; [Leioa] : University of the Basque Country , cop. 2012