1. Anamthawat-Jónsson , K. 2012 Hybridisation, introgression and phylogeography of Icelandic birch Anamthawat-Jónsson, K 117 144.
2. Anonymus , 1990 Birkenhölzer www.holzhandel.de/birkenhölzer.html
3. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III;APG III (Angiosperm Phylogeny Group);Bot. J. Linnean Soc,2009
4. Brummit , R. K. 2001 World geographical scheme for recording plant distributions
5. Scientific assessment of traditional knowledge on firewood and fodder values in Sikkim, India;Chettri;For. Ecol. Manage,2009