@article{AA_2012_24_4_a5,
     author = {H. K\"onig and V. Milman},
     title = {An operator equation characterizing the {Laplacian}},
     journal = {Algebra i analiz},
     pages = {137--155},
     year = {2012},
     volume = {24},
     number = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AA_2012_24_4_a5/}
}