If you want a clear and fuller presentation of the Gospel, it is hard to find a better one than this, written in 1650, “The Sum of Saving Knowledge” by James Durham and David Dickson.
Here is an excellent introduction to the subject of Covenant Theology (“Introduction: On Covenant Theology” by J.I. Packer). It was originally written as an introduction to another book, but it is a stand alone essay that will be helpful for anyone who is trying to get an initial grasp on this essential part of Reformed Theology.
Baptism & the Lord’s Supper
A biblical case for infant baptism: “Infant Baptism: How My Mind has Changed” by Dennis E. Johnson (Professor of Practical Theology at Westminster Seminary in California)
Essay against the growing practice of ‘paedo-communion’, “What Mean Ye?” by Dr. Richard Bacon.
A Reformed Defense of Infant Baptism, “A Contemporary Reformed Defense of Infant Baptism” by Dr. R. Scott Clark.
Worship is regulated by God in His Word…here is an excellent introduction to “The Regulative Principle of Worship” by Terry Johnson.
Our worship is to be directed to God and not an activity that has our pleasure as the goal. Here is an excellent work on the subject of, “Pleasing God in Our Worship” by Dr. Robert Godfrey.
This link will take you to a helpful video called “Purity of Worship” by Pastor Jeff Stivason of Grace RPC (Gibsonia, PA) on the Regulative Principle of Worship and Psalm singing acappella.