New archaeological researches on the transition period to the Bronze Age in the Siret and Nistru areas, the Horodiştea-Gordinesti culture - Alaiba, Ruxandra (The Thracian world at the crossroads of civilizations. 1. Proceedings of the 7th International Congress of Thracology, Constanţa-Mangalia-Tulcea, 20-26 may 1996., 1997)