@article{AFM_2009_34_2_a7,
     author = {Juha Lehrb\"ack},
     title = {Necessary conditions for weighted pointwise {Hardy} inequalities},
     journal = {Annales Fennici Mathematici},
     pages = {437--446},
     publisher = {mathdoc},
     volume = {34},
     number = {2},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AFM_2009_34_2_a7/}
}