@article{MZ_1963__82_170175,
     author = {Erik Ellentuck},
     title = {Solution of a problem of {R.} {Friedberg.}},
     journal = {Mathematische Zeitschrift},
     pages = {101--103},
     publisher = {mathdoc},
     volume = {82},
     year = {1963},
     url = {http://geodesic.mathdoc.fr/item/MZ_1963__82_170175/}
}