Late Cainozoic Floras of Iceland : 15 Million Years of Vegetation and Climate History in the Northern North Atlantic

by Denk, Thomas, Grímsson, Friðgeir, Zetter, Reinhard, Leifur A. Símonarson
Published 2011

Pollen Terminology : An illustrated handbook

by Hesse, M., Halbritter, Heidemarie, Zetter, Reinhard, Weber, Martina, Buchner, Ralf, Frosch-Radivo, Andrea, Ulrich, Silvia
Published 2009