Charged anisotropic Finch–Skea–Bardeen spheres in f(R) gravity with Karmarkar condition M. Farasat Shamir, Ammara Usman and Tayyaba Naz Eur. Phys. J. Plus, 136 1 (2021) 55 Published online: 07 January 2021 DOI: 10.1140/epjp/s13360-020-01027-x