@article{CMUC_1969_10_2_a12,
     author = {Pt\'ak, Vlastimil},
     title = {A remark on compactness of embeddings},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {315--318},
     year = {1969},
     volume = {10},
     number = {2},
     zbl = {0181.13704},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1969_10_2_a12/}
}