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2. English translation: Dif. Equat., 34, No. 11, 1537-1546 (1998).
3. 2. S. D. Ivasyshen, S. D. Eidel'man, "2b-parabolic equations with degeneration in a part of the variables," Dokl. Akad. Nauk SSSR, 360, No. 3, 303-305 (1998) (in Russian).
4. 3. S. D. Ivasyshen, I. P. Medyns'kyi, "Classical fundamental solution of degenerate Kolmogorov-type equation whose coefficients are independent of the variables of degeneration," Bukov. Mat. Zh., 2, No. 2-3, 94-106 (2014) (in Ukrainian).
5. 4. S. D. Ivasyshen, I. P. Medynsky, "Classical fundamental solution of the Cauchy problem for ultraparabolic Kolmogorov-type equations with two groups of spatial variables of degeneration. I," Mat. Met. Fiz.-Mekh. Polya, 60, No. 3, 9-31 (2017) (in Ukrainian)