@article{Terras1979,
  author    = {{Riho Terras}},
  title     = {{On the existence of a density}},
  journal   = {{Acta Arithmetica}},
  year      = {{1979}},
  volume    = {{35}},
  pages     = {{101--102}},
  note      = {{MR 80h:10066}},
}