6The diagram is made according to European Commission, Key Facts and Figures about European Union. Printed in Belgium, 2004 p. 26.
7Social Insurance and Allied Services, Report by Sir William Beveridge. Presented to Parliament by Command of His Majesty, November 1942. From Internet Modem History Sourcebook.
8Samuelson, Paul A. The Pure Theory of Public Expenditure [ J ]. Review of Economics and Statistics. 36 ( November) , 1954. p387 - 398.
9James M. Buchanan. An Econmic Theory of Clubs[J]. Economics. 32(February), 1965.