1. Kibble, T.W.B. [1976], `Topology of cosmic domains and strings’, J.Phys. A9, 1387. Kibble, T.W.B. [1980], `Some implications of a cosmological phase transition’, Phys. Rep. 67 183.
2. Vilenkin, A. [1981], `Cosmological density fluctuations produced by vacuum strings’, Phys. Rev. Lett. 46 1169. Erratum: Phys. Rev. Lett. 46, 1496.
3. Zel’dovich, Ya.B. [1980], `Cosmological fluctuations produced near a singularity’, M. N. R. A. S. 192 663.
4. Vilenkin, A. & Shellard, E.P.S. [1994], Cosmic strings and other topological defects (Cambridge University Press).
5. Vilenkin, A., & Everett, A.E. [1982], `Cosmic strings and domain walls in models with Goldstone and pseudo-Goldstone bosons’, Phys. Rev. Lett. 48 1867.