Instrumental Duet B-Flat Clarinet,Guitar,Instrumental Duet - Level 4 - Digital Download SKU: A0.1077993 Composed by F. Sor. Arranged by Klas Krantz. Classical. Score and parts. 12 pages. Amadeus Music #682195. Published by Amadeus Music (A0.1077993). Fernando Sor (1778 – 1839) was a Spanish/French guitarist and composer, born in Barcelona. In Spain he is sometimes known as the Beethoven of the Guitar.