Analyse palynologique de sites prehistoriques du Pays Basque: Premiers resultats pour les grottes de Lezetxiki et Urtiaga - Sánchez Goñi, María Fernanda (The late Quaternary in the Western Pyrenean Region: Proceed. of the international Conference on the environment and the human society in the Western Pyrenees and the Basque Mountains during the upper Pleistocene and the Holocene. (Gasteiz/Vitoria, 3-5 May 1990)., 1992)