Onyekwere, Sixtus Cyprian. “The Impact of Research and Development (R&D) Expenditure on Productivity Growth: A Panel Data Evidence from the UK Manufacturing Sector”. Asian Journal of Economics and Empirical Research 6, no. 2 (December 20, 2019): 205–215. Accessed April 19, 2024. http://asianonlinejournals.com/index.php/AJEER/article/view/1177.