Probing the dark matter issue in f(R)-gravity via gravitational lensingM. Lubini, C. Tortora, J. Näf, Ph. Jetzer and S. CapozzielloEur. Phys. J. C, 71 12 (2011) 1834DOI: https://doi.org/10.1140/epjc/s10052-011-1834-8