With no explanation, label each line with "O", "event-other", "location-GPE", "person-artist/author", "art-writtenart", "art-broadcastprogram", "art-film", "art-music", "art-other" or "art-painting" preceded by ":".
David
Mason
is
especially
noted
for
his
historical
novel
in
verse
,
``
Ludlow
``
,
about
the
Ludlow
Massacre
in
Ludlow
,
Colorado
,
on
April
20
,
1914
.
David:person-artist/author
Mason:person-artist/author
is:O
especially:O
noted:O
for:O
his:O
historical:O
novel:O
in:O
verse:O
,:O
``:O
Ludlow:art-writtenart
``:O
,:O
about:O
the:O
Ludlow:event-other
Massacre:event-other
in:O
Ludlow:location-GPE
,:O
Colorado:location-GPE
,:O
on:O
April:O
20:O
,:O
1914:O
.:O