@article{10_4064_ba55_3_2,
     author = {Ond\v{r}ej Kurka},
     title = {On {Borel} {Classes} of {Sets} of {Fr\'echet} {Subdifferentiability}},
     journal = {Bulletin of the Polish Academy of Sciences. Mathematics},
     pages = {201--209},
     publisher = {mathdoc},
     volume = {55},
     number = {3},
     year = {2007},
     doi = {10.4064/ba55-3-2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ba55-3-2/}
}