Siliceous microfossils (Diatoms - Bacillariophyceae) from neogene deposits of the Valdarno area (Tuscany, Italy) preliminary results - Witkowski, Andrzej 1955-; Bak, Małgorzata; Wawrzyniak-Wydrowska, Brygida (Verl. Documenta Naturae, 2001)