It is that same economic equation that prevents me from going the self publishing route at this point in my career. (writerunboxed.com)
But there is a real - life economic equation at work, and a real life lesson. (dotearth.blogs.nytimes.com)
I know Dave Pimentel at Cornell has been trying to categorize this for a while, but this idea of actually assigning economic values to things that are usually left out of economic equations, like the cost of cleaning water, you know, so do you want to talk about that a little bit more. (scientificamerican.com)