Dell' Isola, F. and Ruta, G. (1997) “Outlooks in Saint-Venant theory III. Torsion and flexure in sections of variable thickness by formal expansions”, Archives of Mechanics, 49(2), pp. 321–343. Available at: http://am.ippt.gov.pl/index.php/am/article/view/v49p321 (Accessed: 17 January 2026).