@article{CRMATH_2009__347_21-22_1265_0,
     author = {Alberico, Teresa and Cianchi, Andrea and Sbordone, Carlo},
     title = {Fractional integrals and $ {A}_{p}$-weights: {A} sharp estimate},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {1265--1270},
     publisher = {Elsevier},
     volume = {347},
     number = {21-22},
     year = {2009},
     doi = {10.1016/j.crma.2009.09.001},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2009.09.001/}
}