@article{doring:1971:dab,
    author = {D{\"o}ring, B.},
     title = {\"{U}ber die {D}oppelnullstellen der {A}bleitung der
              {B}esselfunktion},
   journal = {Angewandte Informatik},
    volume = {13},
      year = {1971},
     pages = {402–406},
  language = {German},
     zblno = {0224.65012}}