@article{687,
      author       = "Bijlsma, H. and Paresi, C. and Richardson, J. and XIII.
                      Congress of the International Society for Photogrammetry,
                      Helsinki, 1976. Commission VI",
      title        = "Action Research at the ITC in Some Techniques of Mastery
                      Learning: Preliminary Steps in the Photogrammetry Department
                       ",
      year         = "1976",
      note         = "1 sv.",
}