@article{IM_1968__6_141949,
     author = {U. KRENGEL},
     title = {A {Local} {Ergodic} {Theorem.}},
     journal = {Inventiones mathematicae},
     pages = {329--333},
     year = {1968},
     volume = {6},
     zbl = {0165.37402},
     url = {http://geodesic.mathdoc.fr/item/IM_1968__6_141949/}
}