@article{MOMA_1978__85_177867,
     author = {William A. Veech},
     title = {Quasiregular {Points} and {Time} {Changes.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {245--252},
     publisher = {mathdoc},
     volume = {85},
     year = {1978},
     zbl = {0398.28022},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1978__85_177867/}
}