@book{Krueger1973,
  author    = {Kr{\"u}ger, Hans-Peter},
  title     = {Erlebte Interaktionsh{\"a}ufigkeiten als soziometrische Maße},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41230},
  publisher      = {Universit{\"a}t W{\"u}rzburg},
  year      = {1973},
  abstract  = {No abstract available},
  language  = {de}
}
@incollection{CranachEllgring1973,
  author    = {Cranach, Mario von and Ellgring, Johann Heinrich},
  title     = {Problems in the recognition of gaze direction},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-42147},
  publisher      = {Universit{\"a}t W{\"u}rzburg},
  year      = {1973},
  abstract  = {No abstract available},
  language  = {en}
}