Another Greek work that Norton completed at Eton in the same year was the Sancti Gregorii Nazianzeni in Julianum Invectivae DUAE, in quarto.
"A Short History of English Printing, 1476-1898"
Henry R. Plomer
DUAE dextrae were two pipes both playing the treble.
"The Student's Companion to Latin Authors"
George Middleton Thomas R. Mills
