<s>
DTBook	B-Language
(	O
an	O
acronym	O
for	O
DAISY	O
Digital	O
Talking	O
Book	O
)	O
or	O
DAISY	O
XML	B-Protocol
is	O
a	O
XML-based	O
document	O
file	O
format	O
.	O
</s>
<s>
Unlike	O
other	O
document	O
file	O
formats	O
such	O
as	O
ODF	B-Application
DTBook	B-Language
puts	O
a	O
strong	O
emphasis	O
on	O
structural	O
encoding	O
,	O
but	O
in	O
comparison	O
to	O
other	O
structural	O
file	O
formats	O
such	O
as	O
DocBook	B-Protocol
and	O
TEI	B-Language
it	O
is	O
fairly	O
simple	O
.	O
</s>
<s>
DTBook	B-Language
was	O
developed	O
by	O
the	O
Daisy	O
Consortium	O
as	O
an	O
accessible	O
file	O
format	O
similar	O
to	O
HTML	B-Language
,	O
with	O
special	O
regard	O
to	O
the	O
requirements	O
of	O
the	O
visually	O
impaired	O
.	O
</s>
<s>
NIMAS	O
(	O
National	O
Instructional	O
Materials	O
Accessibility	O
Standard	O
)	O
–	O
a	O
U.S.	O
standard	O
for	O
electronic	O
books	O
for	O
the	O
visually	O
impaired	O
–	O
defines	O
a	O
subset	O
of	O
DTBook	B-Language
XML	B-Protocol
elements	O
.	O
</s>
<s>
NIMAS	O
documents	O
are	O
valid	O
according	O
to	O
the	O
DTBook	B-Language
DTD	B-Language
.	O
</s>
