@article{MZ_1977__157_172600,
     author = {Christoph Kopf},
     title = {Remarks on a {Lemma} in {Ergodic} {Theory.}},
     journal = {Mathematische Zeitschrift},
     pages = {97--100},
     publisher = {mathdoc},
     volume = {157},
     year = {1977},
     zbl = {0367.28012},
     url = {http://geodesic.mathdoc.fr/item/MZ_1977__157_172600/}
}