UFOs: Where do they come from?

PARTIAL list of Helmut Abt; Achelous; George Adamski; Aetherius Society; Araguari River; Wilfredo Arevalo; APRO; Aurlands fjord; avro car; Bernina Mountains; Black Elk; British Interplanetary Society; Bullaren Lake; Caioba-Seahorse; Cairo Mill; Cape of Good Hope; CIA; CTA; cyborg; Dakelia barrcks; Defense intelligence Agency; demonic UFO; Durban; embryonic disc; entity; ETI; flying disc; foo fighter; Gateshead; Gorton; Ground Saucer Watch; GSW; Gulf of Fenice; Heinola; Hulst; humanoid; Ibiza; Karlskrona; Kinnula; Lake Mjosa; Lake Siljan; Lavoux; River Lea; Loch Ness; mandala; etc., etc. FULL Where do They Come From? Contemporary Theories on the Origin of the Phenomenon.