Lelyakov, O. P., A. S. Karpenko, and R.-D. O. Babadzhan. “Dynamics of a Non-Rotating Test Null String in the Gravitational Field of a Closed ‘Thick’ Null String Radially Expanding or Collapsing in the Plane Z =”. Ukrainian Journal of Physics 59, no. 11 (October 28, 2018): 1114. Accessed April 18, 2024. https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2018555.