Relativistic anisotropic fluid spheres satisfying a non-linear equation of state Francisco Tello-Ortiz, M. Malaver, Ángel Rincón and Y. Gomez-Leyton Eur. Phys. J. C, 80 5 (2020) 371 Published online: 06 May 2020 DOI: 10.1140/epjc/s10052-020-7956-0