ng, "Models of Topology Change" (e-Print: arXiv:1210.3545 [hep-th]) [70] T. P. Singh, "Gravitational Collapse, Black Holes and Naked Singularities" J. Astrophys. Astr. 20 (1999) 221-232 [arXiv:gr-qc/9805066] [71] T. H. R. Skyrme, "A unified field theory of mesons and baryons" Nucl. Phys. 31 (1962) 556-569