@article{CM_1987__63_1_63_0,
     author = {Lema\'nczyk, M.},
     title = {Ergodic $Z_2$-extensions over rational pure point spectrum, category and homomorphisms},
     journal = {Compositio Mathematica},
     pages = {63--81},
     publisher = {Martinus Nijhoff Publishers},
     volume = {63},
     number = {1},
     year = {1987},
     mrnumber = {906379},
     zbl = {0629.28013},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1987__63_1_63_0/}
}