@article{MAN_1939__116_160033,
     author = {St. Golab},
     title = {\"Uber den {Begriff} der {Pseudogruppe} von {Transformationen}},
     journal = {Mathematische Annalen},
     pages = {768--779},
     publisher = {mathdoc},
     volume = {116},
     year = {1939},
     zbl = {0021.04903},
     url = {http://geodesic.mathdoc.fr/item/MAN_1939__116_160033/}
}