I find the first sentence amusing in its inaccuracy.  " known for her agile and light voice and her silvery, pure tone"?  No, she's known for being the most difficult soprano to work with that anyone has ever known.  This article has no NPOV or it would mention some of her legendary run-ins with conductors and impresarios.  The list of those unwilling to consider working with her may be longer than the list of those who have worked with her and would be willing to do so again.