@article{10_4064_fm182_3_1,
     author = {Petr Holick\'y and Ji\v{r}{\'\i} Spurn\'y},
     title = {$F_{\sigma}$-mappings and the invariance of absolute {Borel} classes},
     journal = {Fundamenta Mathematicae},
     pages = {193--204},
     publisher = {mathdoc},
     volume = {182},
     number = {3},
     year = {2004},
     doi = {10.4064/fm182-3-1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm182-3-1/}
}