@article{MM2_1996__91_3_156214,
     author = {Piotr Hajlasz},
     title = {On approximate differentiability of functions with bounded deformation.},
     journal = {Manuscripta mathematica},
     pages = {61--72},
     publisher = {mathdoc},
     volume = {91},
     number = {3},
     year = {1996},
     zbl = {0868.46024},
     url = {http://geodesic.mathdoc.fr/item/MM2_1996__91_3_156214/}
}