Perturbative solutions of the f(R)-theory of gravity in a central gravitational field and some applicationsNguyen Anh Ky, Pham Van Ky and Nguyen Thi Hong VanEur. Phys. J. C, 78 7 (2018) 539DOI: https://doi.org/10.1140/epjc/s10052-018-6023-6