Revise references to be exact and use APA style

[MrBrezina]

See https://apastyle.apa.org/style-grammar-guidelines/references/examples

Any other recommendations welcome. People should use Markdown for italics (asterisks).

Will need to update the README as well.

[MrBrezina]

I would keep the common sources such as Wikipedia, Unicode as simple as possible to keep the size of the database from getting bloated.

[kontur]

On that note, it would be nice to know the exact page(s) and maybe even #sections of wikipedia referenced. Some languages/scripts have several relevant pages etc. For a changing medium like wikipedia the date when referenced would be helpful; not sure if that is part of the APA but I would think so :)

[MrBrezina]

I will also move them to sources:

[MrBrezina]

And automagically add references to relevant links to Ethnologue and Open Language Archives where available

[kontur]

I will also move them to sources:

Just to be 100%, you're suggesting renaming source: to plural sources:, yes? Okay by me, probably needs a few spots updating in the code, but should be np 👍

In the same go also adding explicit wikipedia language links where we currently reference just "wikipedia" might be good.

Do we need a script to do those automatically? Or at least search/open/edit them automatically?