maps reference sources

Continents.svg is a modified mix of:
https://commons.wikimedia.org/wiki/File:Continents.svg (public domain)
https://en.wikipedia.org/wiki/File:Continents_colour2.svg by Peterfitzgerald (CC-BY-SA 3.0 Unported)


Single continents with countries are all based on:
https://milevski.co/geojson2svg/demo/lands.svg (MIT license)

Except oceania, based on:
https://commons.wikimedia.org/wiki/File:States_and_territories_of_Oceania.svg by Kaidor (CC-BY-SA 4.0)
