1. T. P. Singh, Bulg. J. Phys. 33, 217 (2006).
2. T. P. Singh, in: Re-thinking Time at the Interface of Physics and Philosophy (arXiv:1210.81110), (Eds. T. Filk, A. von Muller), Springer, Berlin-Heidelberg 2015.
3. T. P. Singh, in: Collapse of the Wave Function, (Ed. S. Gao), Cambridge University Press, Cambridge 2018.
4. T. P. Singh, Z. Naturforsch. Pt. A 74, 147 (2019).
5. R. T. Hammond, Rep. Prog. Phys. 65, 599 (2002).