@article{05003622,
title = {Groups of periods for arbitrary maps on groups.},
journal = {Acta Mathematica Universitatis Comenianae. New Series},
volume = {74},
year = {2005},
pages = {229-242},
zbl = {1128.20017},
language = {en},
url = {http://dml.mathdoc.fr/item/05003622}
}
Bonciocat, N.C.; Zaharescu, A. Groups of periods for arbitrary maps on groups.. Acta Mathematica Universitatis Comenianae. New Series, Tome 74 (2005) pp. 229-242. http://gdmltest.u-ga.fr/item/05003622/