Improving regional gravity field and geoid modelling by various use of global geopotential models [Online resource]Märdla, Silja; Ellmann, Artu; Oja, Tõnis; Ågren, Jonas26th IUGG General Assembly 2015 : Prague, Czech Republic, Prague Congress Centre, June 22-July 02, 20152015 / [1] p On the development of the new Nordic gravimetric geoid model NKG2015Ågren, Jonas; Märdla, Silja; Ellmann, Artu26th IUGG General Assembly 2015 : Prague, Czech Republic, Prague Congress Centre, June 22-July 02, 20152015 / [1] p