internal void AddDocument(PdfReader reader, ICollection<int> pagesToKeep)
{
if (!readers2intrefs.ContainsKey(reader) && reader.Tampered)
throw new DocumentException(MessageLocalization.GetComposedMessage("the.document.was.reused"));
reader = new PdfReader(reader);
reader.SelectPages(pagesToKeep);
if (reader.NumberOfPages == 0)
return;
reader.Tampered = false;
AddDocument(reader);
}