John Damascene (or John of Damascus). An Exact Exposition of the Orthodox faith (VII - VIII Centuries) According to: Schaff, Phillip. Nicene and Post-Nicene Fathers series II, Volume 9

( Read on-line, Download as: PDF )

Pomazansky, Michael. Orthodox Dogmatic Theology (1888 - 1988) (Read on-line)

Lossky, Vladimir.Orthodox Theology: an Introduction (1903 -1958) (Read on-line)

Meyendorff, John. Byzantine Theology. Historical Trends and Doctrinal Themes (1973)  (Read excerpts on-line)

Giannaras, Chrēstos. Elements of Faith: An Introduction to Orthodox Theology (1983, 1991) (Read on-line)