Self similar collapse and the Raychaudhuri equationShibendu Gupta Choudhury, Soumya Chakrabarti, Ananda Dasgupta and Narayan BanerjeeEur. Phys. J. C, 79 12 (2019) 1027DOI: https://doi.org/10.1140/epjc/s10052-019-7559-9