Б.А. Дуйсенгалиева and А.С. Науразбекова (2019) “An example of a non-triangulable derivation of a differential polynomial algebra of rank 2”, BULLETIN OF THE L.N. GUMILYOV EURASIAN NATIONAL UNIVERSITY. Mathematics. Computer science. Mechanics series, 128(3), pp. 53–57. Available at: https://bulmathmc.enu.kz/index.php/main/article/view/50 (Accessed: 18 May 2024).