@article{JRAM_1996__478_153843,
     author = {D.H. Armitage and S.J. Gardiner and W. Haussmann and ...},
     title = {Characterization of best harmonic and superharmonic {L1-approximations.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {1--16},
     publisher = {mathdoc},
     volume = {478},
     year = {1996},
     zbl = {0853.31002},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1996__478_153843/}
}