The impossible proof /
Nossack, Hans Erich,1901-.
Lebeck, Michael.
London Barrie & Rockcliff the Cresset P.
1969
This translation originally published, New York: Farrar, Straus & Giroux, 1968. Originally published as 'Unmögliche Beweisoufnahme' in his 'Spirale'. Frankfurt: Suhrkamp, 1956