sentences:  During his studies in Cologne and Madrid, he also studied chamber music with the Amadeus Quartet and members of Quartetto Italiano.Since then, he has appeared as soloist and in recitals in Europe, Asia and America.He has performed with Maria Kliegel and the late Alfredo Kraus, who, during his last years, invited Polo to appear as soloist in his concerts at Covent Garden in London and Maggio Musicale in Florence, Tonhalle in Zurich, and the Musikverein in Vienna.