@article{10_4064_aa135_1_3,
     author = {Zhefeng Xu and Wenpeng Zhang},
     title = {Fourth power mean of character sums},
     journal = {Acta Arithmetica},
     pages = {31--49},
     publisher = {mathdoc},
     volume = {135},
     number = {1},
     year = {2008},
     doi = {10.4064/aa135-1-3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa135-1-3/}
}