1. What Is the Fourth Industrial Revolution?https://iap.unido.org/articles/what-fourth-industrial-revolution
2. IDR2020|UNIDOhttps://www.unido.org/resources-publications-flagship-publications-industrial-development-report-series/idr2020
3. World Economic Forumhttps://www.weforum.org/agenda/2020/09/how-the-4ir-is-driving-a-new-wave-of-energy-innovation/
4. Medical Devices Market Regional Analysis 2020–2025|Global Market Size, Research, Report, Trends, Growth|Medgadg-ethttps://www.medgadget.com/2020/01/medical-devices-market-regional-analysis-2020-2025-global-market-size-research-report-trends-growth.html
5. Global Energy Efficient Devices Market Size 2015–2022, Statistahttps://www-statista-com.libproxy1.nus.edu.sg/statistics/785502/global-energy-efficient-devices-market-size/