@article{10_4064_aa_42_1_79_90,
     author = {Imre Ruzsa},
     title = {Semigroup-valued multiplicative functions},
     journal = {Acta Arithmetica},
     pages = {79--90},
     publisher = {mathdoc},
     volume = {42},
     number = {1},
     year = {1982},
     doi = {10.4064/aa-42-1-79-90},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-42-1-79-90/}
}