diff --git a/doc/23_ref_optional_io.qbk b/doc/23_ref_optional_io.qbk
index 22b2583..57f0677 100644
--- a/doc/23_ref_optional_io.qbk
+++ b/doc/23_ref_optional_io.qbk
@@ -41,10 +41,11 @@ template<class CharType, class CharTrait, class T>
 
 [#reference_operator_ostream]
 
-
-`template <class CharType, class CharTrait, class T>` [br]
- std::basic_ostream<CharType, CharTrait>&` [br]
- operator<<(std::basic_ostream<CharType, CharTrait>& out, optional<T> const& v);`
+```
+template <class CharType, class CharTrait, class T>
+std::basic_ostream<CharType, CharTrait>&
+operator<<(std::basic_ostream<CharType, CharTrait>& out, optional<T> const& v);
+```
 
 * [*Effect:] Outputs an implementation-defined string. The output contains the information about whether the optional object contains a value or not. If `v` contains a value, the output contains result of calling `out << *v`.
 * [*Returns:] `out`.
@@ -52,9 +53,11 @@ template<class CharType, class CharTrait, class T>
 __SPACE__
 [#reference_operator_ostream_none]
 
-`template <class CharType, class CharTrait, class T>` [br]
- std::basic_ostream<CharType, CharTrait>&` [br]
- operator<<(std::basic_ostream<CharType, CharTrait>& out, none_t);`
+```
+template <class CharType, class CharTrait, class T>
+std::basic_ostream<CharType, CharTrait>&
+operator<<(std::basic_ostream<CharType, CharTrait>& out, none_t);
+```
 
 * [*Effect:] Outputs an implementation-defined string.
 * [*Returns:] `out`.
@@ -62,9 +65,11 @@ __SPACE__
 __SPACE__
 [#reference_operator_istream]
 
-`template <class CharType, class CharTrait, class T>` [br]
- std::basic_ostream<CharType, CharTrait>&` [br]
- operator>>(std::basic_istream<CharType, CharTrait>& in, optional<T>& v);`
+```
+template <class CharType, class CharTrait, class T>
+std::basic_ostream<CharType, CharTrait>&
+operator>>(std::basic_istream<CharType, CharTrait>& in, optional<T>& v);
+```
 
 * [*Requires:] `T` is __STD_DEFAULT_CONSTRUCTIBLE__ and __MOVE_CONSTRUCTIBLE__.
 * [*Effect:] Reads the value of optional object from `in`. If the string representation indicates that the optional object should contain a value, `v` contains a value and its contained value is obtained as if by default-constructing an object `o` of type `T` and then calling `in >> o`; otherwise `v` does not contain a value, and the previously contained value (if any) has been destroyed.