Andrianov, I. V., et al. “Buckling of Cylindrical Shells of Variable Thickness, Loaded by External Uniform Pressure”. Technische Mechanik - European Journal of Engineering Mechanics, vol. 20, no. 4, Oct. 2019, pp. 349-54, https://journals.ub.ovgu.de/index.php/techmech/article/view/1102.