Vintage IBM System 370 Reference Summary GX20-1850-3 4th Ed 1976 + Other Guides You will receive all 5. reference summary documents shown in the photos. They are all in Like New to Very Good condition.No writing, tears, or stains in any of the documents. - IBM System/370 Reference Summary GX20-1850-3 Fourth Edition (November 1976) Had a crease but has sat flat for many many years so almost unnoticeable.- IMB OS/VS2 TSO Command Language Reference Summary GX28-0646-3 Fourth Edition (January 1976) Like new condition.- IBM Data Facility Hierarchical Storage Manager Version 2 Release 6.0 User Commands Reference Summary GX35-5036-06 Like new condition.- TRX Security and Performance for Today's TSO User Guide 8162-TRX-2 (03-07-90) Like new condition.- Interactive Output Facility (IOF) Operator's Quick Reference Summary IOF Release 7, September 1991 Very good condition FREE shipping within 2 business days of receiving payment.Thank you for your interest.