https://www.danubeportal.com/ God info om Donauvejen
https://www.skipperguide.de/wiki/Hauptseite
https://www.openseamap.org/index.php?id=openseamap&no_cache=1
https://www.navinaut.com/#/routeplanner
https://waterkaarten.app/?fbclid=IwAR0-GhZdKgOv_Yh7cOW4icpwT4MNSRAdIlugySmlYcoFB6OM1EzPm2sY9Ng