Electronic Gneuss-Lapidge Book: Sotheby’s sale catalogue for 21 Nov. 1972, pl. 3 Referenced in: facs: 504.3 - London, Collection of S.J. Keynes Esq., s.n. (a single leaf; with two further leaves in Cambridge, MA, Harvard University, Houghton Library Typ 612 and Tokyo, T. Takamiya, MS 89 [a leaf in a collection consisting of 29 single leaves])