@article{TE_1987_1987_1_a2,
     author = {Ruiz Espejo, Mariano},
     title = {Dise\~nos muestrales admisibles para el estimador {Horvitz-Thompson.}},
     journal = {Trabajos de estad{\'\i}stica},
     pages = {45-50},
     publisher = {mathdoc},
     volume = {2},
     number = {1},
     year = {1987},
     language = {es},
     url = {http://geodesic.mathdoc.fr/item/TE_1987_1987_1_a2/}
}