1. Donnelly R. J.,Quantized Vortices in Helium II(Cambridge University Press, 1991).
2. Vortex Formation in a Stirred Bose-Einstein Condensate
3. Vilenkin A. and Shellard E. P. S.,Cosmic Strings and other Topological Defects(Cambridge University Press, 1994).
4. An introduction to the theory of dual models and strings