Lelyakov, O. P., A. S. Karpenko, and R.-D. O. Babadzhan. “Scalar-Field Potential Distribution for a Closed ‘Thick’ Null String Moving in the Plane Z =”. Ukrainian Journal of Physics, vol. 59, no. 5, Oct. 2018, p. 547, doi:10.15407/ujpe59.05.0547.