ON-LINE DOC FOR ROFF?

[WAGREICH at bbna.ARPA]

IS  THERE  ANY  ON-LINE USER DOCUMENTATION FOR ROFF THAT EXPLAINS
THE COMMANDS AND GIVES EXAMPLES?  I'D APPRECIATE  ANY  GOOD  USER
DOC FOR ROFF.

THANKS.   I  HOPE  I  DON'T  GET  A  MILLION  COPIES  OF THE SAME
DOCUMENT!