SamoilenkoV. G., and SamoilenkoYu. I. 2014. “Asymptotic Multiphase Solitonlike Solutions of the Cauchy Problem for a Singularly Perturbed Korteweg–de-Vries Equation With Variable Coefficients”. Ukrains’kyi Matematychnyi Zhurnal 66 (12), 1640–1657. https://umj.imath.kiev.ua/index.php/umj/article/view/2252.