 He has served as guest concertmaster with many orchestras including OSESP Brazil, (1999-2003), Teatro Comunale di Bologna, Teatro Bellini di Catania (1990), Orchestra Internazionale D'Italia, and Orchestra Sinfonica Siciliana.Among Master classes conducted by Greco were Drew University in New Jersey (1999-2000), Maracaibo Conservatory in Venezuela (2005) and the Tchaikovsky Conservatory in Santa Severina, Italy (2013).Formerly in the collection of Maestro Greco were a Marino Capicchioni violin and a good Giuseppe Fiorini.