ArmandsCelms Assessment of elevation differences of precised levelling between different epochs of measurements / ArmandsCelms // Вісн. Нац. ун-ту "Львів. політехніка". - 2005. - № 66. - С. 113-117. - Библиогр.: 5 назв. - англ.
This article is about first class leveling measurements made in three campagnes in Latvia: from 1929 till 1939; from 1967 till 1974; from 2000 till 2004 in lines Kolka - Rucava, Riga - Plavinas - Riga and Ainazi - Riga. There are discused obtained elevations and changed values of them in different epochs. There is also aviable assessment about changes acomplished given.