@article{NUMA_1972__20_132177,
     author = {Lois Mansfield},
     title = {On the {Variational} {Characterization} and {Convergence} of {Bivariate} {Splines.}},
     journal = {Numerische Mathematik},
     pages = {99--114},
     publisher = {mathdoc},
     volume = {20},
     year = {1972},
     zbl = {0233.65005},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1972__20_132177/}
}