@article{2876,
author = {Schaefer, Paul},
title = {Mappings of positive integers and subspaces of m},
journal = {Portugaliae mathematica},
volume = {38},
year = {1979},
pages = {27-38},
zbl = {0503.47028},
mrnumber = {0682353},
language = {en},
url = {http://dml.mathdoc.fr/item/2876}
}
Schaefer, Paul. Mappings of positive integers and subspaces of m. Portugaliae mathematica, Tome 38 (1979) pp. 27-38. http://gdmltest.u-ga.fr/item/2876/