xquery retreive data from xml file

I would like to find all libraries with same number of books availbles and as many as empty shelves as the library called "Oxford".

    <librarycollections>
    <library>
    <id>1</id>
    <library_name> oxford <library_name>
    <name>DBMS</name>
    <availble_books>2</availble_books>
    <empty_shelves>5</empty_shelves>
    </library>

    for $x in doc("filename.xml")/librarycollections/library/
        where $x/@available_books = available_books and $x/empty_shelves ="oxford"
        retunrn...

The result I'm trying to get is like this :
Empty shelves/number of books/ library name

    <li>2 empty, 8 bookes @ Greenwich library </li>
    <li>5 empty, 8 bookes @ UCL library </li>

Appreciate any help.
Thank you