@article{MET_1967__12_175341,
     author = {M.P. Singh},
     title = {Ratio cum {Product} {Method} of {Estimation}},
     journal = {Metrika},
     pages = {34--42},
     publisher = {mathdoc},
     volume = {12},
     year = {1967},
     zbl = {0173.20504},
     url = {http://geodesic.mathdoc.fr/item/MET_1967__12_175341/}
}