@article{MZ_1975__145_172276,
     author = {Franz-J\"urgen Delvos and H.-W. K\"osters},
     title = {On the {Variational} {Characterization} of {Bivariate} {Interpolation} {Methods.}},
     journal = {Mathematische Zeitschrift},
     pages = {129--138},
     publisher = {mathdoc},
     volume = {145},
     year = {1975},
     zbl = {0296.41003},
     url = {http://geodesic.mathdoc.fr/item/MZ_1975__145_172276/}
}