The two grammars pictured on the left and the right were both produced in Naples by the same publishing outfit in consecutive years. The Sbordone volume is the 3rd edition published in 1964. The Cupaiuolo tome is from 1963 and specifically notes on the title page that the lectures contained therein were delivered to "gli studenti dell'Inst. Univ. "Orientale" di Napoli." F. Sbordone is known mainly as a papyrologist and editor of Greek texts. Fabio Cupaiuolo published a number of very useful bibliographical surveys on Latin grammar and metrics, which I give references for in my book, plus a book on Latin adverbs (Cupaiuolo 1967), which I didn't cite. The Sbordone book is really very barebones and sketchy. The one noteworthy feature is the the built-in selection of archaic inscriptions illustrating pre-classical norms. The Cupaiuolo book is a lot more detailed and devotes about 60 pages (about 20 percent of the book) to a discussion of the formation of adverbs, clearly a subject of special interest to Professore Cupaiuolo. How Libreria scientifica editrice was talked into publishing both these works virtually at the same time is a bit of a mystery!
Cupaiuolo, F. 1963. Lezioni di grammatica storica latina. Naples: Libreria scientifica editrice.
———. 1967. La formazione degli avverbi in latino. Naples: Libreria scientifica editrice.
Sbordone, F. 1964. Grammatica storica della lingua latina. Con appendice di testi epigrafici, 3rd edition. Naples: Libreria scientifica editrice.