We prefer internal links to wiki pages over external links leading directly to web resources. Any source worth citing deserves a page that hints at the worth that can be read without leaving the lineup.
See Link Word for preferred external links.
Thompson chose direct external links when journaling his 15 June 2018 deep dive into roots of agile. I internalized these links while reading so as to strengthened my understanding of his journey.
See Collaborative Link for more internalization benefits.