Hennies, Manfred O.E., and Matti Raudjärv. “Kryptowährungen. Gedanken Zur gegenwärtigen Situation”. Estonian Discussions on Economic Policy 26, no. 1-2 (November 5, 2018). Accessed January 19, 2022. http://ojs.utlib.ee/index.php/TPEP/article/view/14505.