There is a way to prove if those sources are genuine but you don't have resources to do so. However to say "there is no way to prove they are true or not" is fa

There is a way to prove if those sources are genuine but you don't have resources to do so. However to say "there is no way to prove they are true or not" is far from true. Such documents can be cross-referenced with other documents we know are genuine, simply this requires research you have no time nor resource to conduct. But there are others out there who have both time and resources. I have seen some documents about my home government (not USA) which were all (to the last one) true.