4Burton Weisbrod, "Toward a Theory of the Voluntary Nonprofit Sector in a Three - Sector Economy;" in E. Phelps,ed , Altruism Morality and Economy Theory .
5Henry Hansmann , "The Role of Nonprofit Enterprise ,"Yale Law Journal , Vol. 89 (1980), pp. 835-901.
6Lester M. Salamon : American' s Nonprofits Sector"The Government Role in American' s Mixed Economy of Welfare.
7Susan Rose - Ackerman , "Altruism, Ideological Entrepreneurs and the Nonprofit Firm," p. 131.
