Georgievska, Slobodanka S. “A BOUNDARY PROBLEM OF THE SIXTH ORDER AS A PRODUCT OF BOUNDARY PROBLEMS OF THE SECOND AND THE THIRD ORDERS”. Matematichki Bilten 26, no. 1 (January 1, 2002): 117–124. Accessed August 15, 2026. https://bilten.smm.org.mk/index.php/bilten/article/view/1658.