Zanidis, Themistoklis. “The World Defense Expenditure 2019 and Trends in the Covid19 Era”. HAPSc Policy Briefs Series 1, no. 1 (June 30, 2020): 140–148. Accessed April 5, 2025. https://ejournals.epublishing.ekt.gr/index.php/hapscpbs/article/view/24959.