There are +1000 studies that have the keyword push up in them-on PubMed. A reliable site that gathers studies in the fields of medicine/health/exercices/supplements/...
But honestly, this is an easy exercise to build up(and imo one of the most fun ones). Just be sure to use proper technique(body straight, and go down with your arms, not your belly/legs/...) Most of the basic rosters out there will help, even of you find 5 different ones. They will most likely all work for a beginner.
You'll also begin to feel for yourself after a while what you're capable of and what method works best for you.