Barrois: Dactylologie et langage primitif, Paris, 1850, Firmin Didot freres.
The library of the New York Institution contains a copy of this very rare edition, bearing the title Abacus atque velustissima Latinorum per digitos manusque numerandi (quinetiam loquendi) consuetudo, etc., Ratisbonae, 1532.
For an exhaustive account of the gesture speech in Anglo-Saxon monasteries and of the Cistercian monks, who were under rigid vows of silence, see F. Kluge: Zur Geschichte der Zeichensprache.—Angelsachsische indicia Monaslerialia, in International Zeitschrift fur Allgemeine Sprachwissenschaft, II. Band, I. Halfte. Leipzig, 1885.