@article{10_1007_s10587_012_0068_8,
     author = {Ma, Rong and Zhang, Yulong},
     title = {On a kind of generalized {Lehmer} problem},
     journal = {Czechoslovak Mathematical Journal},
     pages = {1135--1146},
     publisher = {mathdoc},
     volume = {62},
     number = {4},
     year = {2012},
     doi = {10.1007/s10587-012-0068-8},
     mrnumber = {3010261},
     zbl = {1259.11090},
     language = {en},
     url = {https://geodesic-test.mathdoc.fr/articles/10.1007/s10587-012-0068-8/}
}