1. What is Industry 4.0. https://www.epicor.com/en/resource-center/articles/what-is-industry-4-0/
2. The Evolution of Industry 1.0 to 4.0. https://www.seekmomentum.com/blog/manufacturing/the-evolution-of-industry-from-to-4
3. The birth of the electric machines. https://royalsocietypublishing.org/doi/10.1098/rsta.2014.0208
4. The invention of the electric motor. https://www.eti.kit.edu/english/1376.php
5. History of mobile phones and the first mobile phone. https://www.uswitch.com/mobiles/guides/history-of-mobile-phones/