70sscifiart:

Title: 1977 Mufon UFO Symposium Proceedings. The cover is yellow, with six illustrations of different types of UFOs on top of graphs.ALT
Title: 1978 Mufon UFO Symposium Proceedings. The cover is white, with an illustration depicting four types of close encounter: UFOs in the sky for the first kind, a landing leg leaving a footprint for the second, an alien in a doorway for the third, and two aliens holding a human in front of their ship for the fourth.ALT
Title: 1979 Mufon UFO Symposium Proceedings. The cover is lime green, with "UFO" printed over and over like a wallpaper design. A magnifying glass is over this design.ALT

MUFON – the “oldest and largest civilian UFO-investigative organization in the United States” – kindly gave me permission to include these great 1977-‘79 flyer designs in my art book Worlds Beyond Time.

My favorite is the 1978 flyer, because it elegantly illustrates the four different kinds of close encounter: Visual sighting, physical evidence, encountering an entity, and abduction. Just very cool design!

If you want a lot more retro UFO art, this link lists all the stores that are selling it (some might be out of stock, but most are good).