I made a modification of the R package rpart for researching purposes. The license is GPL-2 | GPL-3.
The modification is simple but it is critical for another package that I have developed. I would like to upload it to Github for reproducibility purposes.
I have two questions:
How should I acknowledge the authors of rpart? Is a forking in github enough? Can I include myself as an author?
Am I obliged to use GPL license?