California students building electric ultralight from scratch - AOPA
Amazon.it: Amateur-Built Aircraft and Ultralight Flight Testing Handbook (Advisory Circular No. 90-89A) - Transportation, U. S. Department of, Administration, Federal Aviation - Libri
Ultralight aviation - Wikipedia
Ultralight Aircraft | National Air and Space Museum
Backyard Flyer II, Valley Engineering Backyard Flyer series of experimental and part 103 legal ultralight aircraft.