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- [5] R&D in the metallurgical industry toward the 21st century [J]. JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY, 1997, 49 (04): : 33 - 37
- [6] Have R&D Spillovers Declined in the 21st Century? [J]. FISCAL STUDIES, 2019, 40 (04) : 561 - 590