Instrumental Duet Flute,Guitar,Instrumental Duet - Level 4 - Digital Download SKU: A0.531279 Composed by W. Peterson-Berger. Arranged by Klas Krantz. Classical,Romantic Period. Score and parts. 3 pages. Amadeus Music #2033989. Published by Amadeus Music (A0.531279). Wilhelm Peterson-Berger (1867-1942), was a Swedish composer and music critic. As a composer, his main musical influences were Grieg and Wagner as well as Swedish folk idiom.