JELER, Grigore Eduard. “BRIEF HISTORICAL MILESTONES ON THE EVOLUTION OF UAV SYSTEMS: 1914 - 1939”. BULLETIN OF "CAROL I" NATIONAL DEFENCE UNIVERSITY 9, no. 3 (October 20, 2020): 137–143. Accessed May 7, 2024. https://revista.unap.ro/index.php/bulletin/article/view/670.