@article{10_4064_aa_60_4_349_358,
     author = {K. Alnia\c{c}ik},
     title = {On semi-strong {U-numbers}},
     journal = {Acta Arithmetica},
     pages = {349--358},
     publisher = {mathdoc},
     volume = {60},
     number = {4},
     year = {1991},
     doi = {10.4064/aa-60-4-349-358},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-60-4-349-358/}
}