In VSI Fortran, you can use the following alternative syntax for
  octal and hexadecimal constants:

                  Alternative Syntax   Equivalent
                  ------------------   ----------
     Octal        '0..7'O              O'0..7'
     Hexadecimal  '0..F'X              Z'0..F'

  In the above syntax forms, you can use a quotation mark(") in place
  of an apostrophe (').