Further reading
SAS Macro Programming for Beginners by Susan J. Slaughter and Lora D. Delwiche, available here: https://support.sas.com/resources/papers/proceedings/proceedings/sugi29/243-29.pdf
Logging the Log Magic: Pulling the Rabbit out of the Hat by Adel Fahmy, available here: https://www.lexjansen.com/pharmasug/2010/TT/TT08.pdf
Don't Be a SAS® Dinosaur: Modernizing Programs with Base SAS 9.2 Enhancements by Warren Repole Jr., available here: https://analytics.ncsu.edu/sesug/2009/FF011.Repole.pdf
A SASAUTOS Companion: Reusing Macros by Ronald Fehd, available here: https://www.lexjansen.com/nesug/nesug05/pm/pm12.pdf
Using SAS Macro Language and SAS® Pipe to Process State Health by Xiaoting Qin and Cathy M. Bailey, available here: https://support.sas.com/resources/papers/proceedings11/179-2011.pdf