(You do have to scroll through the article to reach the quote)
scroll to nearly the end of the text to see "External Evidence," where you can find a quote from Irenaeus of Lyons, an early church father, on the authorship of Acts
The primary sources for this are the letters themselves! Refer to Paul's references in each. (Hint: these are shared in the Cold-Case book!)
Again, see the gospel of Luke itself to refer to evidence of this