Here is an article for my economist friends: http://www.ncpa.org/iss/sta/2003/pd121103b.html
And this is the original academic work: http://dsl.nber.org/papers/w9844.pdf Sabri
Here is an article for my economist friends: http://www.ncpa.org/iss/sta/2003/pd121103b.html
And this is the original academic work: http://dsl.nber.org/papers/w9844.pdf Sabri