Global asymptotic step like solutions to the singularly perturbed Korteweg-de Vries equation with variable coefficientss - S. I. Ljashko; V. G. Samojlenko; Ju. I. Samojlenko; I. V. Gapjak; N. I. Ljashko; M. S. Orlova (International Scientific Technical Journal «Problems of Control and Informatics», 2020)