XQuery content between two singleton tags

[Diwanji]

do you know to do XQuery query for selection of content between two singleton tags, e.g.\[code\]<pb n="1"/> this is <foo>page</foo> number one<pb n="2"/> this is <bar>page</bar> number two<pb n="3"/> this is <x>page</x> number three\[/code\]and I want for example content of second page, so between \[code\]<pb n="2"/>\[/code\] and next \[code\]<pb/>\[/code\]. Output should be then:\[code\] this is <bar>page</bar> number two\[/code\]