REXX - sgml/signature GitHub Wiki
- ftp://ftp.software.ibm.com/software/os390/db2server/books/REXXV5.PDF
- ftp://ftp.software.ibm.com/software/cics/vse/dfhwrx00.pdf
- https://www.ibm.com/support/knowledgecenter/ssw_i5_54/books/sc415728.pdf
- https://www-01.ibm.com/servers/resourcelink/svc00100.nsf/pages/zOSV2R3SA232283/$file/bpxb600_v2r3.pdf