@article{13887, author = "Simonsen, O. and Second Symposium for the Commission on Recent Crustal Movements held in Aulanko in Finland in August 1965", title = "Is the Levelling Datum for a Continental Levelling Network so Stable that it Would Permit the Determination of Secular Movements as Accurate as Modern Precise Levellings May be Observed ", year = "1965", note = "1 brož., 2 brož.", }