It's here, in a post by Russell Roberts at Cafe Hayek, and in the linked paper from which he draws. Roberts demolishes, along the way, the lunacies of Paul Krugman, whose Leftism blinds him to economic principles that even he once understood.
Related posts:
Why Class Warfare Is Bad for Everyone
Fighting Myths with Facts
Debunking More Myths of Income Inequality
Ten Commandments of Economics
More Commandments of Economics
Zero-Sum Thinking
On Income Inequality
The Causes of Economic Growth