@unpublished{TUW-219175, author = {Umnig, Elke Maria}, title = {Precise GNSS}, year = {2013}, note = {talk: Retreat der Forschungsgruppe H{\"o}here Geod{\"a}sie 2013, Hohe Wand, Austria; 2013-05-13 -- 2013-05-15} }