DOUKAS, Ioannis D.; AMPATZIDIS, Dimitrios; KAMPOURIS, Vassileios. THE VALIDATION OF THE TRANSFORMATION BETWEEN AN OLD GEODETIC REFERENCE FRAME AND A MODERN REFERENCE FRAME, BY USING EXTERNAL SPACE TECHNIQUES SITES: THE CASE STUDY OF THE HELLENIC GEODETIC REFERENCE SYSTEM OF 1987. Boletim de Ciências Geodésicas, [S. l.], v. 23, n. 3, 2017. Disponível em: https://revistas.ufpr.br/bcg/article/view/55432. Acesso em: 4 jan. 2026.