Data Sets for Book Examples, available in Stata format and other formats at:
https://dataverse.harvard.edu/dataverse/crt
Link to Greene SAS Macro for obtaining highly constrained randomizations:
https://github.com/ejgreene/ccr-sas
Chaudhary/Moulton SAS Macro for obtaining highly constrained randomizations:
Download SAS Macro (note: this is a .docx file, you'll need to copy into a text .sas file (this website provider only allows media files).