@book{Linsenmair1971,
  author    = {Linsenmair, Karl Eduard},
  title     = {Hvorfor synger fuglene?},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44530},
  publisher      = {Universit{\"a}t W{\"u}rzburg},
  year      = {1971},
  abstract  = {No abstract available},
  language  = {mul}
}
@book{Linsenmair1972,
  author    = {Linsenmair, Karl Eduard},
  title     = {Varf{\"o}r sjunger faglarna? : F{\aa}gels{\aa}ngens formeroch funktioner},
  isbn      = {91-27-24248-X},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44521},
  publisher      = {Universit{\"a}t W{\"u}rzburg},
  year      = {1972},
  abstract  = {No abstract available},
  language  = {mul}
}