references .Ecological Economics:Principles and Applications,Herman E. Daly and Joshua Farley,Island Press,2004. Ecological Economics:An Introduction,Mick Common and Sigrid Stagl,Cambridge University Press,2005. .Natural Capital and Human Economic Survial(Second Edition) by Thomas Prugh et al.,1999,Lewis Publishers. Toward Sustainable Development:An Ecological Economics Approach by Philip A.Lawn,2001,Lewis Publishers.references ⚫ Ecological Economics: Principles and Applications, Herman E. Daly and Joshua Farley, Island Press, 2004. ⚫ Ecological Economics: An Introduction, Mick Common and Sigrid Stagl, Cambridge University Press, 2005. ⚫ Natural Capital and Human Economic Survial (Second Edition) by Thomas Prugh et al., 1999, Lewis Publishers. ⚫ Toward Sustainable Development: An Ecological Economics Approach by Philip A. Lawn, 2001, Lewis Publishers