1. L. M. Pismen, Vortices in Nonlinear Fields (Clarendon, Oxford, 1999).
2. C. J. Pethick and H. Smith, Bose—Einstein Condensation in Dilute Gases (Cambridge Univ. Press, Cambridge, 2002).
3. L. P. Pitaevskii and S. Stringari, Bose—Einstein Condensation (Oxford Univ. Press, Oxford, 2003).
4. P. G. Kevrekidis, D. J. Frantzeskakis, and R. Carretero-González, The Defocusing Nonlinear Schrödinger Equation: From Dark Solitons and Vortices to Vortex Rings (SIAM, Philadelphia, 2015).
5. B. Y. Rubinstein and L. M. Pismen, Phys. D (Amsterdam, Neth.) 78, 1 (1994).