Evolution of spherical overdensity in Chaplygin gas model Amin Rezaei Akbarieh, Mohammad Ahmadi, Yousef Izadi, Shahabeddin M. Aslmarand and Warner A. Miller Eur. Phys. J. C, 80 5 (2020) 391 Published online: 11 May 2020 DOI: 10.1140/epjc/s10052-020-7960-4