The Oneness of God: Volume 1 (Series in Pentecostal Theology, Vol 1)

Here are a few good resources, I would recommend. Understanding the Godhead by Rev. Gregory Riggenhttps://a.co/d/0cbQn3Yy - modern, lots of depth but in an every day presentation. Our God is One - Dr. Talmadge Frenchhttps://www.goodreads.com/en/book/show/1542650.Our_God_Is_One - history driven and extremely academic in writing style. The Oneness of God (Vol. 1) - Rev. David K. Bernardhttps://a.co/d/08JL6GI1 - considered classic Pentecostal literature now, well known and good material. These are not affiliate links. I just copied them from the various apps. You can find most of these online free anyway. I hope this helps you.