<s>
refer	O
is	O
a	O
program	O
for	O
managing	O
bibliographic	O
references	O
,	O
and	O
citing	O
them	O
in	O
troff	B-Language
,	O
nroff	B-Device
,	O
and	O
groff	B-Application
documents	O
.	O
</s>
<s>
It	O
is	O
implemented	O
as	O
a	O
preprocessor	B-General_Concept
.	O
</s>
<s>
refer	O
was	O
written	O
by	O
Mike	O
Lesk	O
at	O
Bell	O
Laboratories	O
in	O
or	O
before	O
1978	O
,	O
and	O
is	O
now	O
available	O
as	O
part	O
of	O
most	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
A	O
free	O
reimplementation	O
exists	O
as	O
part	O
of	O
the	O
groff	B-Application
package	O
.	O
</s>
<s>
,	O
refer	O
sees	O
little	O
use	O
,	O
primarily	O
because	O
troff	B-Language
itself	O
is	O
not	O
used	O
much	O
for	O
longer	O
technical	O
writing	O
that	O
might	O
need	O
software	O
support	O
for	O
reference	O
and	O
citation	O
management	O
.	O
</s>
<s>
,	O
some	O
reference	B-Application
management	I-Application
software	I-Application
(	O
for	O
instance	O
,	O
RefWorks	B-Library
)	O
will	O
import	O
refer	O
data	O
.	O
</s>
<s>
The	O
author	O
then	O
can	O
refer	O
to	O
it	O
in	O
their	O
troff	B-Language
,	O
groff	B-Application
,	O
or	O
nroff	B-Device
document	O
by	O
listing	O
keywords	O
which	O
uniquely	O
match	O
this	O
reference	O
:	O
</s>
<s>
+	O
Database	O
fieldsrefer	O
man	B-Protocol
page	I-Protocol
,	O
,	O
dated	O
2July	O
2016	O
.	O
</s>
