Rexx Programming/How to Rexx/quotation mark
In rexx, strings can be quoted using either singlequotes or doublequotes.
Quotation Marks Within a Literal String 
In order to use literal singlequote characters within a string, the string can be enclosed using doublequotes:
say "Here's how we use an apostrophe within a string"
In order to use literal doublequote characters within a string, the string can be enclosed using singlequotes:
say 'Here we are using "doublequotes" within a string'
Back To Back Quotation Marks 
It is possible to use backtoback quotation marks to represent a single quotation mark within the string:
say 'Heres back to back' /* Note the back to back quotation mark for an apostrophe */