@article{MET_1986__33_176031,
     author = {P. Laake},
     title = {Optimal {Estimates} and {Optimal} {Predictors} of {Finite} {Population} {Characteristics} in the {Presence} of {Nonresponse.}},
     journal = {Metrika},
     pages = {69--77},
     publisher = {mathdoc},
     volume = {33},
     year = {1986},
     url = {http://geodesic.mathdoc.fr/item/MET_1986__33_176031/}
}