We know from local and international research that housing is a key source of health inequality.
Human capital management is a key source of resilient business performance.
Tourism is a key source of income for Tunisia, accounting for 6.5% of its gross domestic product.
Weather is a key source of income risk for many firms and households, particularly in emerging market economies.
"In Uganda, where the banana is a key source of nutrition, there is considerable vitamin A deficiency and also iron deficiency in diets," he said.
It is a key source of Ireland's failure to reach international human rights standards and of the state's failure to meet its obligations to vindicate women's human rights.
This hurts, because manufacturing, with its competitive pressures and its demand for technological innovation, is a key source of economic growth for developing countries.
Pakistan is a key source of support for the Taliban, providing arms, food, fuel and, not least, thousands of volunteers for its fighting forces.
However, when a company experiences an environmental shock like the one Fujifilm and Kodak faced, heterogeneity is a key source of robustness.
The fact that so many people find themselves with rising incomes and a rising standard of living is a key source of support.
Along with Iceland, it is a key source of cod imports into the UK, which has over-fished its own waters.
