Saudi, M. H. M., Sinaga, O., Roespinoedji, D., & Razimi, M. S. A. (2019). Environmental Sustainability in the Fourth Industrial Revolution: The Nexus between Green Product and Green Process Innovation. International Journal of Energy Economics and Policy, 9(5), 363–370. Retrieved from https://econjournals.com/index.php/ijeep/article/view/8281