@article{MM2_1995__87_4_156101,
     author = {A. Knopfmacher and R. Warlimont},
     title = {Distinct {Degree} {Factorizations} in {Additive} arithmetical semigroups.},
     journal = {Manuscripta mathematica},
     pages = {481--488},
     publisher = {mathdoc},
     volume = {87},
     number = {4},
     year = {1995},
     zbl = {0848.11045},
     url = {http://geodesic.mathdoc.fr/item/MM2_1995__87_4_156101/}
}