• Dynamic lighting system for workplaces at Northen latitudesKoppel, TarmoScientific journal of Riga Technical University. Safety of technogenic environment2012 / p. 39-44 https://www.researchgate.net/publication/266389024_Dynamic_Lighting_System_for_Workplaces_at_Northern_Latitudes
• Dynamic lighting system for workplaces at northern latitudesKoppel, TarmoRiga Technical University 53rd International Scientific Conference dedicated to the 150th anniversary and the 1st Congress of World Engineers and Riga Polytechnical Institute/RTU Alumni : 11-12 October 2012, Riga, Latvija : [abstracts]2012 / p. 454 : ill https://www.researchgate.net/publication/266389024_Dynamic_Lighting_System_for_Workplaces_at_Northern_Latitudes