String Quartet No. 21 in D Major, K. 575 "Prussian No. 1" - I. Allegretto (Mozart: 1. Allegretto [String Quartet No.21 in D, K.575 "Prussian No.1"]|Ｍｏｚａｒｔ：　１．　Ａｌｌｅｇｒｅｔｔｏ　［Ｓｔｒｉｎｇ　Ｑｕａｒｔｅｔ　Ｎｏ．２１　ｉｎ　Ｄ，　Ｋ．５７５　”Ｐｒｕｓｓｉａｎ　Ｎｏ．１”］)