@article{CC_2003_32_3_a13,
     author = {Rolewicz, Stefan},
     title = {On \ensuremath{\sigma}-porous and {\ensuremath{\Phi}-angle-small} sets in metric spaces},
     journal = {Control and Cybernetics},
     pages = {671--681},
     publisher = {mathdoc},
     volume = {32},
     number = {3},
     year = {2003},
     zbl = {1137.49305},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CC_2003_32_3_a13/}
}