1. Key Figures on Europe: Statistics Illustrated, Page 12;Strandell,2018
2. Small and medium-sized enterprises in terms of their goals
3. IMPULS-Industrie 4.0 Readinesshttps://industrie40.vdma.org/documents/4214230/26342484/Industrie_40_Readiness_Study_1529498007918.pdf/0b5fd521-9ee2-2de0-f377-93bdd01ed1c8
4. https://www.pwc.com/gx/en/industries/industries-4.0/landing-page/industry-4.0-building-your-digital-enterprise-april-2016.pdf
5. Developing Transformation Roadmaps for a Digital Enterprise_World Economic Forumhttps://www.weforum.org/projects/developing-transformation-roadmaps-for-a-digital-enterprise