Maintenance work on the ZORA databases is scheduled for Wednesday 22 May 2019 from 20:00-22:00. During this period ZORA and JDB will not be available. Thank you for your understanding.
Legat, Klaus; Skaloud, Jan; Schmidt, Ronald (2006). Reliability of direct georeferencing: A case study on practical problems and solutions: Final Report on Phase 2. Dublin: EuroSDR.