@article{GDZPPN002393166,
title = {Solution of a problem of R. Friedberg.},
journal = {Mathematische Zeitschrift},
volume = {82},
year = {1963},
pages = {101-103},
url = {http://dml.mathdoc.fr/item/GDZPPN002393166}
}
Ellentuck, Erik. Solution of a problem of R. Friedberg.. Mathematische Zeitschrift, Tome 82 (1963) pp. 101-103. http://gdmltest.u-ga.fr/item/GDZPPN002393166/