Indicates what characters (if any) are used to delimit character
  constants in list-directed and namelist output.  It takes the
  following form:

  DELIM = del

  del  Is a character expression with one of the
       following values:

  'APOSTROPHE'  Indicates that apostrophes delimit character
                constants. All internal apostrophes are doubled.

  'QUOTE'       Indicates that quotation marks delimit character
                constants.  All internal quotation marks are doubled.

  'NONE'        Indicates that character constants have no
                delimiters.  No internal apostrophes or quotation
                marks are doubled. This is the default.

  DELIM is only allowed for files connected for formatted data
  transfer; it is ignored during input.