Coletti's treatise is not in print, but Cesare Corsi quotes from it in his Thoughts on singing and the didactic works of Filippo Coletti(in Italian)]. Coletti claims that the masters of singing of the Rossini and previous eras, didn't use written or printed singing 'methods', but rather a sheet of paper. On this they noted wrote exercises, and kept adding trills, gruppetti etc. to these sheets which were used for many years. Thus the pupils mastered emission of voice, agility, accents, phrasing, breath control, registration, colouring and pronunciation. each time with the addition of more sheets of paper. Coletti claims that the great secret of the art was in the very first sheet the pupil received "(F. Coletti, The school of singing, p. 9)[61] "The Italian schools of singing, ... arrived at such a point of fame, that the primary cities of Europe, charmed of the beauty and skill of our voices, received us everywhere with applause and rewards. The Italian opera abroad became the meeting point of the most selected part of the nation, and our singing method has become a model of beauty and elegance. The Italian theatre is still vigorous in those countries of progressive civility, but only by name and language, since the works and the companies that represent it are no longer exclusively Italian, but cosmopolitan. Next to the Italian artist one can hear – in our own theatres as well – the French artist, the German, the Spanish and the English; and they all sing in their own language, nevertheless with emission of voice and corresponding pronunciation to the nature of their native language." (F. Coletti, The school of singing p. 56). Cesare Corsi, Le riflessioni sul canto e le opera didattiche di Filippo Coletti
Fairtile, Linda B. "Verdi at 200: Recent Scholarship on the Composer and His Works." Notes 70, no. 1 (2013): 9–36. Accessed 27 August 2020. http://www.jstor.org/stable/43672695.
Zicari, M. (2016). Index. In Verdi in Victorian London (pp. 337–348). Cambridge, UK: Open Book. Retrieved 27 August 2020. JSTORj.ctt1d41d0q.31
searcholdmagazines.com
Coletti was seen on the cover for Opera News in January 1974, in Delfico's caricature; a discussion of Delfico and this specific caricature, see: Anna Maria Ioannoni Fiore, Fiorella Fumo and Tania Gatto, Music in Art, Vol. 34, No. 1/2, Music, Body, and Stage: The Iconography of Music Theater and Opera (Spring–Fall 2009), pp. 229–243, Published by: Research Center for Music Iconography, The Graduate Center, City University of New York