@article{MS2_1982__50_166782,
     author = {Seppo Granlund},
     title = {An {L...-Estimate} for the gradient of extremals.},
     journal = {Mathematica Scandinavica},
     pages = {66--72},
     publisher = {mathdoc},
     volume = {50},
     year = {1982},
     zbl = {0489.49009},
     url = {http://geodesic.mathdoc.fr/item/MS2_1982__50_166782/}
}