@article{1102905668,
author = {Friedlander, Eric M.},
title = {Extension functions for rank $2$, torsion free abelian groups.},
journal = {Pacific J. Math.},
volume = {61},
number = {2},
year = {1975},
pages = { 371-380},
language = {en},
url = {http://dml.mathdoc.fr/item/1102905668}
}
Friedlander, Eric M. Extension functions for rank $2$, torsion free abelian groups.. Pacific J. Math., Tome 61 (1975) no. 2, pp. 371-380. http://gdmltest.u-ga.fr/item/1102905668/