这个是我找到的这篇文章的最新版本。用于代替2004年3月那一版Matching and learning in cities: Evidence from patent data。
Working Paper NO. 06-14
URBAN DENSITY AND THE RATE OF INVENTION
Gerald Carlino
Satyajit Chatterjee
Robert Hunt
Federal Reserve Bank of Philadelphia
First Draft: March 2004
This Draft August 2006
Supersedes Working Paper NO. 04-16/R