1938, George Melville Bolling and Bernard Bloch, Language, volume 14, page 224 (Linguistic Society of America)
The theory that there was a spontaneous development of an obscure vowel in final position on certain occasions in Old Italian has gained general currency and has been carried on in the works of the main authorities.
2000, Guido Mensching, Infinitive Constructions with Specified Subjects: A Syntactic Analysis of the Romance Languages, pages 30{1} and 31{2} (Oxford Studies in Comparative Syntax; ISBN 019513303X, 9780195133035)
{1} [… T]his configuration, in which the infinitive clause is a prepositional complement of a noun, could not be found in the documentary evidence of (Tuscan) Old Italian. Another diverging property in this example is the preverbal subject after prepositions, no longer common in Old Italian at the end of the fifteenth century […]
{2} [… T]he examples show the use of nonauxiliary verbs. Though similar to Old Italian, this is another difference from contemporary Italian.