Credo Magazine
The latest issue of Credo Magazine (pdf) brings together “some of the sharpest thinkers in order to bring our minds back to the beauty, glory, and majesty of our triune God—Father, Son, and Holy Spirit.” The purpose? “[T]o help us think deeper thoughts about how God is one essence and three persons, and what impact the Trinity has on who we are and what we do as believers.”
Here are links to three articles:
Teaching Series
Ligonier Ministries has six free videos of R. C. Sproul lecturing on the doctrine of the Trinity. The lectures include: