References

Other sources

http://www.blueplanetbiomes.org/siberian_tundra.htm

http://environment.nationalgeographic.com/environment/habitats/tundra-threats/

http://www.huffingtonpost.com/2010/11/21/siberia-climate-change-methane_n_786554.html

http://www.wunderground.com/wximage/siberia/0?gallery=
http://www.biology-blog.com/blogs/archives/Animal-science-blog/1173912282-Feb-5-2007.htmlh