@misc{Ellgring1978,
  author    = {Ellgring, Johann Heinrich},
  title     = {Comment to J. Rojahn: "Validity and reliability of data from naturalistic observational studies - problems and alternatives"},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-42520},
  year      = {1978},
  abstract  = {No abstract available},
  language  = {en}
}