This paper deals with the physical location of firms although other interpretations are also possible. It is a well-known fact that firms in certain industries tend to cluster. However, since you would expect competition to be more intense when goods are less diversified in a locational sense...

Multinational enterprises (MNEs) are important in transmitting technology across national borders. Not only do they allow for transfer of technology within the firm, but it is also believed that they are important channels for international R&D spillovers as well. This paper analyzes empirically...