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