In arguments with Miron's supporters, they bring up the standard libertarian arguments in favor of child labor. So I did a little hunting.
Can Developing Countries Afford to Ban or Regulate Child Labor?, by Mark Weisbrot, Robert Naiman, and Natalia Rudiak, points out that modern developing countries are as rich we were in the first world when we gave it up. Along the way they disabuse a number of other foolish arguments.
In my Privatization and Deregulation index.