-Specify a system file or portable file's name, a data set name
-(@pxref{Datasets}), or a file handle name (@pxref{File Handles}). The
-dictionary in the file will be read, but it will not replace the
-active dataset's dictionary. The file's data will not be read.
+The @subcmd{FROM} clause is mandatory. Use it to specify a system
+file or portable file's name in single quotes, a data set name
+(@pxref{Datasets}), or a file handle name (@pxref{File Handles}).
+The dictionary in the file is be read, but it does not replace the active
+dataset's dictionary. The file's data is not read.