1. Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, DE-14473 Potsdam, Germany
2. Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775, USA
3. Permafrost Institute, Siberian Branch Russian Academy of Science, RU-677010 Yakutsk, Russia
4. Faculty of Geology, Moscow State University, Vorobievy Gory, RU-119992 Moscow, Russia
5. Senckenberg Institute for Quaternary Palaeontology, Am Jakobskirchhof 4, DE-99423 Weimar, Germany
6. University Bern, Institute of Geology, Baltzerstrasse 1-3, CH-3012 Bern, Switzerland