@article{10_4064_cm_53_1_137_146,
     author = {\v{S}. Porubsk\'y and W. Schwarz},
     title = {Sums of additive functions on arithmetical semigroups},
     journal = {Colloquium Mathematicum},
     pages = {137--146},
     publisher = {mathdoc},
     volume = {53},
     number = {1},
     year = {1987},
     doi = {10.4064/cm-53-1-137-146},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-53-1-137-146/}
}