المؤلفون: World Bank
المصدر: :47-82
URL الوصول: http://elibrary.worldbank.org/doi/pdf/10.1596/978-1-4648-0220-1http://elibrary.worldbank.org/doi/abs/10.1596/978-1-4648-0220-1_ch4http://elibrary.worldbank.org/doi/pdf/10.1596/978-1-4648-0220-1_ch4http://elibrary.worldbank.org/doi/abs/10.1596/978-1-4648-0220-1