@article{AM2_1992__43_1_137445,
     author = {S.P. Zhou},
     title = {On a problem of {Davison.}},
     journal = {Aequationes mathematicae},
     pages = {90--93},
     year = {1992},
     volume = {43},
     number = {1},
     zbl = {0757.39001},
     url = {http://geodesic.mathdoc.fr/item/AM2_1992__43_1_137445/}
}