In addition, these articles were always written by people who were working in the industry. This can be partly explained by the political and economic context of that time and also because research in Spain has traditionally been limited due to the little investment efforts made in this matter. In 1960, investment in research rep- resented only 0.2% of GDP (Gross Domestic Product) and in 1975 was up only 0.34% of GDP. In fact, it was not until 2003 that Spain achieved the 1% of GDP investment in research, still well below the European average of 2% (Hernández, 2007).