@article{10_4064_fm_114_1_79_83,
     author = {Giuseppina Russo and Santi Valenti},
     title = {On the k-pseudo-symmetrical approximate differentiability},
     journal = {Fundamenta Mathematicae},
     pages = {79--83},
     publisher = {mathdoc},
     volume = {114},
     number = {1},
     year = {1981},
     doi = {10.4064/fm-114-1-79-83},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-114-1-79-83/}
}