{{ with .Page.Param "Author" }}
    {{ $hosts := where $.Site.RegularPages ".Section" "host" }}
    {{ $filesWithAuthor := where $.Site.RegularPages ".File.BaseFileName" . }}
    {{ $author := index ($filesWithAuthor | intersect $hosts) 0 }}
    by <a href="{{ $author.Permalink}} ">{{ $author.Title }}</a>
{{ end }}