1. Manufacturing, Value Added (% of GDP); The World Bankhttps://data.worldbank.org/indicator/NV.IND.MANF.ZS
2. Manufacturing Statistics—NACE Rev. 2 Statistics. Eurostathttps://ec.europa.eu/eurostat/statistics-explained/index.php?title=Manufacturing_statistics_-_NACE_Rev._2&oldid=502915
3. Communication from the Commission to the European Parliament, the European Council, the Council, the European Economic and Social Committee and the Committee of the Regions: A New Industrial Strategy for Europe; EU Publicationshttps://op.europa.eu/en/publication-detail/-/publication/8ac0eb6c-6394-11ea-b735-01aa75ed71a1/language-en
4. Derivation of a cost model to aid management of cnc machine tool accuracy maintenance;Shagluf;J. Mach. Eng.,2015