Ashraf, Z., M. A. Choudhry, and A. Hanif. “A HYBRID PI CONTROL SCHEME FOR AIRSHIP HOVERING”. The Nucleus 49, no. 2 (March 26, 2012): 115–127. Accessed November 25, 2024. http://thenucleuspak.org.pk/index.php/Nucleus/article/view/805.