"CICS Maintenance Methodology" at http://www.mainframehelp.com/cics_maint_methodology.htm

CICS Installation Guide: Section 2.6.1 - Defining CICS SVCs to your MVS, at http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/dfha1p03/2.6.1, and Section 2.6.2 - Using more than one version of the CICS Type 3 SVC, at http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/dfha1p03/2.6.2