@article{MAN_1963__151_161085,
     author = {E. ENGELER},
     title = {A {Reduction-Principle} for {Infinite} {Formulas.}},
     journal = {Mathematische Annalen},
     pages = {296--303},
     year = {1963},
     volume = {151},
     zbl = {0114.24504},
     url = {http://geodesic.mathdoc.fr/item/MAN_1963__151_161085/}
}