共 50 条
[1]
Adams JamesD., 2008, INVENTION DISCOVERY
[5]
[Anonymous], 2006, STATA J
[6]
[Anonymous], 1970, EC CITIES
[7]
[Anonymous], 2001, NBER PATENT CITATION
[8]
[Anonymous], 2010, INTEGRATED PUBLIC US
[9]
[Anonymous], 2004, Economics of Innovation and New Technology, DOI DOI 10.1080/1043859042000234302

