(:
    Build a portfolio of paper titles per author.
    Report the list of authors who have more than one paper.
    Over bibliography.xml.
    parke godfrey 2013-11-06

    Fixed so no duplicates.
:)

<bigwig>{
    let $portfolios :=
        <portfolios>{
            for $author in doc("bibliography.xml")//author/text()
            group by $author
            order by $author
            return
                <portfolio author='{$author}'>{
                    for $paper in doc("bibliography.xml")
                                    //paper[.//author/text() = $author]
                    return $paper/title
                }</portfolio>
        }</portfolios>
    for $author in $portfolios/portfolio
    let $count := count($author/title)
    where $count > 1
    return <author count='{$count}'>{$author/@author/data()}</author>
}</bigwig>