@article{MZM_1977_21_2_a14,
     author = {E. Z. Dyment},
     title = {Two theorems on finite unions of regressive immune sets},
     journal = {Matemati\v{c}eskie zametki},
     pages = {259--269},
     publisher = {mathdoc},
     volume = {21},
     number = {2},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1977_21_2_a14/}
}