Read any of the books above or watch this Yotube documentary http://www.youtube.com/watch?v=7vyVe-6YdUk where hundreds of high ranking officials in Govt, military, aviation etc. are willing to go on the record and testify under oath, of some of these events.
That is not documentation. That is eye-witness testimony.
Edit: I won't sit through 2hrs of slow-talking elderly men reminiscing about that time they see some unexplained lights in the sky. It is difficult to take proponents of the ET-hypothesis serious if they always point to such bad evidence.