I'm sorry, but I meant a source other than a 2 hour video criticising a book. And before you say it's a good video, I actually tried watching it once. I think I got through about 30 minutes of saying nothing of substance when I gave up. I actually recommend the exercise - try rewatching and make a note when he actually makes an argument or references a source.

Right above my comment is another linking the wikipedia page on IQ heritability. That would be a good example of a source. Meta-studies are a good option. Longitudinal studies are a decent one. Single studies are usually useless, but they're at least a good starting point for a productive conversations.