

This sheet of calculations in black ink is inscribed twice in blue ink by Feynman. The first reads, "To Egon Lehmkuhl, Richard P. Feynman." The second is near the lower edge of the sheet, with an arrow pointing to the calculations, "Trying to understand what happens when protons collide. R. P. F."
Feynman manuscripts are scarce and seldom seen on the market.