Testimonials are enough to convince people for now.
Who could look on these monuments without reflecting on the vanity of mortals in thus offering up testimonials of their respect for persons of whose very names posterity is ignorant?
How much energy is wasted in Italy in trying to write the novel that obeys all the rules. The energy might have been useful to provide us with more modest, more genuine things, that had less pretensions: short stories, memoirs, notes, testimonials, or at any rate, books that are open, without a preconceived plan.
I think even if I did the research mentioned above, it would be a total waste of money because if those people don't believe in the testimonials, they won't believe in the research at all. They would say that I made it all up. So why waste money?