The written word is assumed to have been reflected upon and revised by its author, reviewed by authorities and editors. It is easier to verify or refute, and it is invested with an impersonal and objective character, which is why, no doubt, you have referred to yourself in your thesis as “the investigator” and not by your name; that is to say, the written word is, by its nature, addressed to the world, not an individual. The written word endures, the spoken word disappears; and that is why writing is closer to the truth than speaking.
Consider this basis for asserting the truth of printed words, against the nature of internet-published ones. Those also endure; but only sort of (websites often die or get rearranged). More importantly, the internet always biases us toward newer information, so that as a web resojrce ages, it becomes less true.
