I appreciated Steven Olderr’s letter exhorting us to support our local bookstore [Viewpoints, Dec. 9]. May I add some theoretical justification for his argument? Economists have done the rigorous research to show that supporting local businesses enriches the local economy. Buying from, say, Amazon, or even Walmart, enriches Jeff Bezos or the Walton family. Keep the profit here in Oak Park, and it recirculates.