6 links
A Brief Introduction to Trinitarian Faith
abortionessay.com
Explores the nature of the Trinity, and puts forth Thomistic arguments that the doctrine of One God in three persons is not polytheistic.
Discovering the Spirit In the Trinity
spirithome.com
Discusses how the early Church grew into a conviction about the Holy Spirit as God.
On the Incarnation
ccel.org
Writings by Athanasius, the 4th century A.D. bishop of Alexandria, defending the Christology of the Council of Nicaea.
The Trinity
observations.net
Presents the doctrine of the Trinity from a Christian Neoplatonic perspective.