One resource, written in bite-size articles and in layman's terms, is Understood.org.
A few links to begin with -
1) https://www.understood.org/
2) https://www.understood.org/en/articles/understanding-impulsivity
3) https://www.understood.org/en/articles/self-control-what-it-means-for-kids

When looking for information on impulse control, you might also use the search term "executive function."
A few links to begin with -
1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4084861/
2) https://developingchild.harvard.edu/science/key-concepts/executive-function/
3) https://www.sciencedirect.com/topics/psychology/executive-function
4) https://www.hoagiesgifted.org/blog_hop_executive_function.htm
5) https://www.davidsongifted.org/?s=executive+function

When it comes to advocacy, Wrightslaw is an invaluable resource.
A few links to begin with -
1) https://www.wrightslaw.com/
2) https://www.wrightslaw.com/blog/organization-homework-problems-executive-function-issues/

Best wishes on your research!