“Riemann-Hilbert Approach for the Integrable Nonlocal Nonlinear Schr\"odinger Equation With Step-Like Initial Data”. Visnyk of V. N. Karazin Kharkiv National University. Ser. Mathematics, Applied Mathematics and Mechanics, vol. 88, Dec. 2018, pp. 4-16, https://doi.org/10.26565/2221-5646-2018-88-01.