1. Norwegian University of Life Sciences; Department of Plant and Environmental Sciences; P.O. Box 5003; NO-1432 Ås; Norway
2. Aarhus University; Department of Geoscience; Nordic Laboratory for Luminescence Dating; Risø DTU, P.O. Box 49; DK-4000; Roskilde; Denmark
3. Jagiellonian University; Institute of Geography and Spatial Management; ul. Gronostajowa 7; 30-387; Cracow; Poland