NOT KNOWINNG THE TYPE OF ASSEMBLY TO IMPLEMENT HERE??

<ObjectDataProvider x:Key="books" ObjectType="{x:Typed:BookData}" MethodName="getallbooks"/>

ITS SHOWING ME AN ERROR

Error    1    The type 'x:Typed' was not found. Verify that you are not missing an assembly reference and that all referenced assemblies have been built.    C:\Users\Sameer\Documents\Visual Studio 2008\Projects\observablecollection\observablecollection\Window1.xaml   7    55    observablecollection

PLEASE HELP ME TO RESOLVE THIS ERROR..THANKS!!!!