Abele, M., Balodis, J., Janpaule, I., Lasmane, I., Rubans, A. and Zariņš, A. 2012. Digital zenith camera for vertical deflection determination. Geodesy and Cartography. 38, 4 (Dec. 2012), 123-129. DOI:https://doi.org/10.3846/20296991.2012.755324.