The main resource that I recommend is the one towards the bottom of the comment: “Motivational Interviewing” by W.R. Miller and Stephen Rollnick. I’ve read the third and fourth editions. The third edition is more concrete but also more complex, and more focused on the field of clinical psychology, while the fourth edition is a shorter book where it’s been generalized more to be more applicable to all kinds of helping relationships, but contains fewer specific examples of clinical practice.

In the second edition they had not yet broken up the concept of “resistance” into “sustain talk” and “discord,” which I found to be a helpful distinction.

About 10% of the book is its bibliography, so if you want more information about a specific claim you can usually find the primary source by following the reference.

Miller and Rollnick are the ones who developed the technique of motivational interviewing, so they have a strong connection to much of the research cited.