There is Wirth's 4 page guide, How to use the Oberon System
https://people.inf.ethz.ch/wirth/ProjectOberon/UsingOberon.p...
Also The Oberon Pi Quick Reference and System User Guide at this project page.
There's a lot of Oberon documentation on Wikibooks:
Oberon seems fascinating and I would like to eventually play around with it in an emulator, but any resources that show how it's being used (as opposed to a description of its design like in Wirth's book for example) would be appreciated.
[0]: https://www.youtube.com/watch?v=dP1xVpMPn8M