@article{MS2_1977__40_166534,
     author = {L. Sario and L.O. Chung and C. Wang},
     title = {Harmonic and polyharmonic degeneracy.},
     journal = {Mathematica Scandinavica},
     pages = {288--292},
     publisher = {mathdoc},
     volume = {40},
     year = {1977},
     zbl = {0367.31003},
     url = {http://geodesic.mathdoc.fr/item/MS2_1977__40_166534/}
}