ZARIŅŠ, Ansis; RUBANS, Augusts; SILABRIEDIS, Gunārs. Digital zenith camera of the University of Latvia. Geodesy and Cartography, [S. l.], v. 42, n. 4, p. 129–135, 2016. DOI: 10.3846/20296991.2016.1268434. Disponível em: https://journals.vilniustech.lt/index.php/GAC/article/view/2421. Acesso em: 9 may. 2025.