@article{GDZPPN002035502, title = {A problem arising in finite population sampling theory.}, journal = {Aequationes mathematicae}, volume = {28}, year = {1985}, pages = {307-312}, zbl = {0584.62010}, url = {http://dml.mathdoc.fr/item/GDZPPN002035502} }
Liu, Tzen-Ping; Thompson, M.E. A problem arising in finite population sampling theory.. Aequationes mathematicae, Tome 28 (1985) pp. 307-312. http://gdmltest.u-ga.fr/item/GDZPPN002035502/