Steve Schwartz writes:

>As far as I know, there's only one Cage string quartet, from, I think,
>1950.  When did he write the others?

Yes, the first string quartet by Cage(String Quartet in Four Parts) was
composed in 1950.  In 1987, he wrote "Music for Four, for String Quartet"
and followed it up in 1989 with "Four for String Quartet".

Cage also composed five works for Percussion Quartet - 1935, 1940, two in
1941, and 1984.  The man wrote a huge amount of music.

Don Satz