Gospel of the Comforter by Steele is a 36 chapter work on the Holy Spirit and different aspects of Him (1897).
Devotional Thoughts by Aitken is many chapter devotional work on various Christian life issues and topics.
10 Fundamental Mistakes of Seventh-day Adventists by Morales is a short work which is an overview the glaring problems with the Seventh-day Adventists.
CARM-Seventh Day Adventist by Matt Slick is a series of pages on this group as well as their version of Scripture, a Clear Word version.
Robert Shaw’s short 1 chapter work on God and the Holy Trinity is an excellent collection of observations and verses that defend the Trinity.
Gaebelein, A.C. – Work of Christ Past, Present and Future. Gaebelein (Brethren) devotes an entire chapter to each one of these three.
Anderson Silence of God theodicy is about when God is silent, the silence of God, which in theology it is theodicy. Why doesn’t God immediately vindicate his children.