2009. Handing over the results of observations 11 absolute gravimetric points on all territory of Vietnam between Vietnam institute of Geodesy and Cartography and Moscow Geodesic Photogrammetrical Enterprise in 20/3/2009. Journal of Geodesy and Cartography. 1 (Sep. 2009), 4. DOI:https://doi.org/10.54491/jgac.2009.1.631.