Help on composer's music? Edvard Grieg?

I have to do a performance critique every quarter for orchestra and this quarter I have to listen to a song by Edvard Grieg and write about it. I found three songs I really like. They are In the Hall of the Mountain King, Morning, and I. Prelude: Allegro Vivace. I found the recordings for free on a href="http://www.last.fm/music/Edvard+Grieg" rel="nofollow"http://www.last.fm/music/Edvard+Grieg/a and I'll pick from one of these. My dilema is that on some I can't tell who performs them, instrumental group or even professional group. I need both in my critique. Please help me if you can. Thank you in advance=]