Audretsch; et al. (2002). "The Economics of Science and Technology". The Journal of Technology Transfer. 27 (2): 157. doi:10.1023/A:1014382532639. S2CID143820412.
Audretsch; et al. (2002). "The Economics of Science and Technology". The Journal of Technology Transfer. 27 (2): 157. doi:10.1023/A:1014382532639. S2CID143820412.