Article: Since re-establishing independence, Estonia has styled itself as the gateway between East and West and aggressively pursued economic reform and integration with the West. Estonia's market reforms put it among the economic leaders in the former COMECON area.[citation needed] In 1994, based on the economic theories of Milton Friedman, Estonia became one of the first countries to adopt a flat tax, with a uniform rate of 26% regardless of personal income. In January 2005, the personal income tax rate was reduced to 24%. Another reduction to 23% followed in January 2006. The income tax rate was decreased to 21% by January 2008. The Government of Estonia finalised the design of Estonian euro coins in late 2004, and adopted the euro as the country's currency on 1 January 2011, later than planned due to continued high inflation. A Land Value Tax is levied which is used to fund local municipalities. It is a state level tax, however 100% of the revenue is used to fund Local Councils. The rate is set by the Local Council within the limits of 0.1–2.5%. It is one of the most important sources of funding for municipalities. The Land Value Tax is levied on the value of the land only with improvements and buildings not considered. Very few exemptions are considered on the land value tax and even public institutions are subject to the tax. The tax has contributed to a high rate (~90%) of owner-occupied residences within Estonia, compared to a rate of 67.4% in the United States.

Question: Who was the source of influence for the flat tax?
Milton Friedman