This is part 3A of a series of teachings given by Howard M. Ervin at the Greater Pittsburg Charismatic Conference in 1973. In this teaching, Dr. Ervin argues for Baptism in the Holy Spirit as a separate and subsequent event from conversion and initiation. He argues that the gospel of Luke and the gospel of John each have their own pneumatology in the way they understand the Spirit.
Ervin, Howard M., "Initiation and Baptism In the Holy Spirit Pt. 3A" (1973). Sermons on the Holy Spirit. 21.