22. Piero della Francesca: Trattato d'abaco. Autograph manuscript. ?1450s. 21.5 by 14 cm (Biblioteca Laurenziana, Florence; MS Ashburnham 359*, fol.3r)
Attributed works:
23. Archimedes: Opera, written by Piero della Francesca. ?1459-70. 28.5 by 21.5 cm. (Biblioteca Riccardiana, Florence; MS Ricc.Lat.106, fol.1r).
Article
Piero della Francesca as Assistant to Antonio d'Anghiari in the 1430s: Some Unpublished Documents