@article{CMUC_1980__21_3_a18,
     author = {Navara, Mirko and Pt\'ak, Pavel},
     title = {On the integration on $\sigma$-classes},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     publisher = {mathdoc},
     volume = {21},
     number = {3},
     year = {1980},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1980__21_3_a18/}
}