Signed typed letter with “Asbóth Aircraft Factory” letterhead.“With reference to our agreement of March 20, 1924 on the s 1 pcs ambulance body, we agreed as follows: Since we cannot complete the body, you will take it over as it is today and finish it for your own account. […] We declare to each other that we have no claims against each other. […] Should the obligation to pay sales tax arise, it will be borne solely by you. Yours sincerely, Asbóth Aircraft Factory. ” Oszkar Asboth (1891–1960) was a Hungarian aviation engineer often credited with the invention of the helicopter.