static void AddAssemblies (XmlNode dest, XmlDocument source)
{
foreach (XmlNode asm in source.SelectNodes ("/Overview/Assemblies/Assembly")) {
var n = asm.Attributes ["Name"].Value;
var v = asm.Attributes ["Version"].Value;
if (dest.SelectSingleNode (string.Format ("Assembly[@Name='{0}'][@Value='{1}']", n, v)) == null) {
dest.AppendChild (dest.OwnerDocument.ImportNode (asm, true));
}
}
}