Two Studies of the Narrowing Gap Between Richer and Poorer Countries

A. Human Capital and the Wealth of Nations: A New Methodology for Measurement of Social and Economic Change in Latin America and Other World Regions
By Michael S. Ray

B. 200 Countries See Two Gaps Narrow, 1810-2010, Poor/Sick and Rich/Healthy (Convergence of 1. Social Conditions [Life Expectancy], and 2. Income [GDP Per Capita In Terms of Purchasing Power of Parity]
By Hans Rosling