I discovered this PDF file not long ago for those interested please read:

The UFO phenomenon remains one of the most persistent and perplexing mysteries of modern times. Encounters have occurred for thousands of years, and the activity shows no signs of slowing, with reports coming from around the world. "UFOs and Aliens" presents an exciting history of extraterrestrial activity on planet Earth, documenting some of the world's best-verified cases. Readers will learn about famous sightings such as the Washington Nationals and the Mexico City sightings; encounter cases of UFO landings and abductions, like the Hopkinsville "goblins," and the Travis Walton alien abduction case; and explore the mystery of whether a UFO crashed near Roswell, New Mexico, in 1947. Everything from infamous hoaxes to the physical evidence of alien implants to government cover-ups are presented here with the best evidence available, so that readers can decide what may be fact and what is, indeed, science fiction.Chapters include: Ancient Astronauts, When UFOs Land, Taken Aboard, UFO Crashes, and Conspiracies and Cover-ups.