The classic 1976 work of Ferdinando Gliozzi, Joel Scherk and David Olive paved the way to a systematic understanding of the rules behind string spectra in cases where only closed strings are present via modular invariance but did not lead to similar progress for models with closed strings, despite the fact that the original discussion was based on the type I string theory.
Luigi Ferdinando Marsigli | Ferdinando Stanley, 5th Earl of Derby | Ferdinando Paer | Ferdinando I de' Medici, Grand Duke of Tuscany | Ferdinando Gorges | Pier Ferdinando Casini | Ferdinando Martini | Ferdinando Fairfax, 2nd Lord Fairfax of Cameron | Ferdinando Ughelli | Ferdinando Sarmi | Ferdinando de' Medici | Ferdinando d'Adda | Carlo Ferdinando Landolfi | San Ferdinando | Francesco Ferdinando d'Avalos | Ferdinando Paër | Ferdinando III de' Medici | Ferdinando II de' Medici, Grand Duke of Tuscany | Ferdinando Gliozzi | Ferdinando Gentile | Ferdinando Fairfax | Ferdinando de' Medici, Grand Prince of Tuscany | Ferdinando de' Medici, Grand Duke of Tuscany | Ferdinando d' Aragona y Guardato, 1st Duke of Montalto | Ferdinando Carulli | Cardinal Ferdinando de' Medici |