1. V. Christianto, Apeiron 11 (1), pp. 112–152 (2004).
2. Singularities are averted by vortices
3. A. Ifa, H. Louati, and M. Rouleux, J. Math. Sci. Univ. Tokyo. 25, pp. 91–127 (2018).
4. V. Christianto and F. Smarandache, Prespacetime J. 11 (1), (2020).
5. V. Christianto, F. Smarandache, and Y, Umniyati, Prespacetime J. 9 (7), (2018).