With no explanation, label each line with "location-GPE", "O", "person-scholar", "organization-education", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting" or "art-writtenart" preceded by ":".
Upon
his
return
to
Sweden
,
Roos
was
appointed
Professor
of
Mathematics
at
Stockholm
University
in
1970
,
and
started
building
a
strong
algebra
school
.
Upon:O
his:O
return:O
to:O
Sweden:location-GPE
,:O
Roos:person-scholar
was:O
appointed:O
Professor:O
of:O
Mathematics:O
at:O
Stockholm:organization-education
University:organization-education
in:O
1970:O
,:O
and:O
started:O
building:O
a:O
strong:O
algebra:O
school:O
.:O