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Jordanus Demonstrationes in Arithmetica . Book Jordanus Nemorarius Demonstrationes in Arithmetica lat it In hoc opere contenta Arithmetica decem libris demonstrata Musica libris demonstrata quattuor Epitome in libros arithmeticos diui Seuerini Boetij Rithmimachie ludus qui et pugna numerorum appellatur Parhisij curarunt vna