@article{20425,
      author       = "Wyrzykowski, T. and IUGG - IAG, 15th General Assembly
                      Moscow, 1 - 14 August 1971",
      title        = "Non - Univocality of up to Date Systematic error Evalution
                      in Precise Levelling at Various average lengths of mean
                      straight lines or Levelling lines proposal of a new
                      evaluation mode of this Error  ",
      note         = "1 s.",
}