Samah, Irza Hanie Abu, et al. “The Impact of Healthcare Expenditure and Healthcare Sector Growth on CO2 Emission Using Dynamic Panel Data System GMM Estimation Model During COVID 19 Crisis”. International Journal of Energy Economics and Policy, vol. 10, no. 6, Oct. 2020, pp. 235-41, https://econjournals.com./index.php/ijeep/article/view/9769.