@article{01973827,
title = {Harmonic },
journal = {Beitr\"age zur Algebra und Geometrie},
volume = {44},
year = {2003},
pages = {309-321},
zbl = {1045.53044},
language = {en},
url = {http://dml.mathdoc.fr/item/01973827}
}
Bejan, C. L.; Benyounes, M. Harmonic . Beiträge zur Algebra und Geometrie, Tome 44 (2003) pp. 309-321. http://gdmltest.u-ga.fr/item/01973827/