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2. American Meteorological Society (2020) Degree-days. In: Glossary of Meteorology. American Meteorological Society, http://glossary.ametsoc.org/wiki/degree-days (Accessed on February 11, 2020).
3. An Introduction to Frozen Ground Engineering;Andersland,1994
4. Patterned ground;Ballantyne,2007
5. Periglacial Geomorphology;Ballantyne,2018