@article{SF_1977__14_186380,
     author = {H.J. Shyr and C. M. Reis},
     title = {A note on a problem of {Hua.}},
     journal = {Semigroup forum},
     pages = {7--14},
     publisher = {mathdoc},
     volume = {14},
     year = {1977},
     zbl = {0358.20066},
     url = {http://geodesic.mathdoc.fr/item/SF_1977__14_186380/}
}