Ivanova-Karatopraklieva I. Infinitesimal bendings of some classes of rotational surfaces with mixed curvature. Ann. Sofia Univ. Fac. Math. and Inf. [Internet]. 1993 Dec. 12 [cited 2024 Nov. 22];85:89-106. Available from: https://annual.uni-sofia.bg/index.php/fmi/article/view/458