@article{10_1007_s10587_015_0217_y,
     author = {Zhang, Han and Zhang, Wenpeng},
     title = {Some new sums related to {D.} {H.} {Lehmer} problem},
     journal = {Czechoslovak Mathematical Journal},
     pages = {915--922},
     publisher = {mathdoc},
     volume = {65},
     number = {4},
     year = {2015},
     doi = {10.1007/s10587-015-0217-y},
     mrnumber = {3441325},
     zbl = {06537700},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10587-015-0217-y/}
}