@article{GDZPPN002036282, title = {A solution to a problem of J. Schwaiger.}, journal = {Aequationes mathematicae}, volume = {33}, year = {1987}, pages = {38-44}, zbl = {0619.39006}, url = {http://dml.mathdoc.fr/item/GDZPPN002036282} }
Gajda, Zbigniew. A solution to a problem of J. Schwaiger.. Aequationes mathematicae, Tome 33 (1987) pp. 38-44. http://gdmltest.u-ga.fr/item/GDZPPN002036282/