bucknell.edu. [2024-02-15]. (原始内容存档于2017-12-19). The Economics of Ecosystems and Biodiversity for the Forestry Sector of Adjara Autonomous Republic, Georgia
Zipf's Law. MathWorld. Zipf's Law examples and modelling (1985) Complex systems: Unzipping Zipf's law (2011) (页面存档备份,存于互联网档案馆) Benford’s law, Zipf’s law